Speaker 1: We run the chapter four, we're going to be talking
Speaker 1: about power and decibels, AC power and basic components Power
Speaker 1: and decibels. You recall Ohms law from your technician training
Speaker 1: E which voltage equals current times resistance. Current can be
Speaker 1: related to voltage divided by resistance, and resistance can be
Speaker 1: voltage over current. So there's a refresher. I know you
Speaker 1: remember all your Ohms law training from your technician class.
Speaker 1: So E is voltage is current ours resistance similar relationship
Speaker 1: between power. Power is equal to voltage times current. Voltage
Speaker 1: can be expressed as power divided by current, and current
Speaker 1: can be expressed as power over energy or over voltage.
Speaker 1: So substituting the omes law equivalents for voltage and current
Speaker 1: allows power to be calculated using resistance. So power is
Speaker 1: equal to the current squared times of resistance, or powers
Speaker 1: equal to the voltage squared divided by the resistance. Find
Speaker 1: out how many watts of electrical power are used in
Speaker 1: four hundred volts dc. DC is supplied to an eight
Speaker 1: hundred owned resistor, you would say, hmm. Power is equal
Speaker 1: to the voltage square divided by resistance. In this case
Speaker 1: four hundred square divided by eight hundred homes six hundred
Speaker 1: and sixty thousand divided by eight hundred or two hundred watts.
Speaker 1: So if I had a four hundred volt signal with
Speaker 1: an eight hundred owned resistor, if that resistor is going
Speaker 1: to dissipate two hundred wats of power. To find out
Speaker 1: how many watts of electrical power are used by a
Speaker 1: twelve volt DC light bulb that draws point two amps,
Speaker 1: you would use. Power is equal to voltage times current,
Speaker 1: in this case twelve volts times point two amps two
Speaker 1: point four watts. Find out how many watts are being
Speaker 1: dissipated when a current of seven million amps flows through
Speaker 1: a well one point two K two five ko resistor. Remember,
Speaker 1: power is equal to the current square times resistance. Were
Speaker 1: given current which is point zero zero seven amps or
Speaker 1: seven million amps times twelve hundred and fifty oms, you'd
Speaker 1: get sixty one point two five milliwatts. And so just
Speaker 1: remember if you're given something in seven million amps, you'd
Speaker 1: sometimes you want to convert it to amps, so it's
Speaker 1: point zero seven amps. To do your calculations, make sure
Speaker 1: you're using like units when you do your conversions. Okay,
Speaker 1: calculating the power or or voltage ratio from dB. Power
Speaker 1: ratio is defined as ten to the minus one log
Speaker 1: of the dB over ten. So voltage is dB divided
Speaker 1: by twenty the log of dB divided by twenty. So
Speaker 1: inverse log notes you refer to this. I remember from
Speaker 1: your school anti log and log what it can be
Speaker 1: referred to. Power ratio of nine dB is ten to
Speaker 1: the minus one of nine over ten, and log of
Speaker 1: minus one of zero point nine is equal to eight.
Speaker 1: So this is probably the most complex math you'll need
Speaker 1: for this course. So don't worry if you're if you're
Speaker 1: going crazy about Oh my gosh, it's not gonna be
Speaker 1: too bad. So a voltage ratio of thirty two dB,
Speaker 1: remember it's thirty two divided by twenty log, So thirty
Speaker 1: two divided by twenty is one point six. Log minus
Speaker 1: one of one point six is forty. So some useful
Speaker 1: things if you double the power or cut it in half.
Speaker 1: There's a three dB change that's a useful thing to
Speaker 1: understand when you're talking about deep about dB. So a
Speaker 1: three dB change is either twice the power or half
Speaker 1: the power, depending on if it's positive or or or negative.
Speaker 1: And so let's say ten a dB is equal to
Speaker 1: the ten log of ten two over one. So ten
Speaker 1: log of two is equal to ten times point three
Speaker 1: three dB. This is where that comes from. So you
Speaker 1: had a ratio change of two to one. I mean
Speaker 1: I've doubled the power, and uh so if you double
Speaker 1: the power, you're gonna get three dB difference. So let's
Speaker 1: take a look at these. So if you're looking percentage
Speaker 1: power is equal to dB over ten, percentage power change
Speaker 1: dB over ten or percent voltage change of dB over twenty.
Speaker 1: That's the way you can convert from dB to percentage.
Speaker 1: I suppose you're using an antenna feed line that has
Speaker 1: a loss of one dB. You can calculate the amount
Speaker 1: of transmitting power that's actually reaching your antenna and how
Speaker 1: much is lost in the feed line. This is how
Speaker 1: you use so let's talk about it. So I've got
Speaker 1: a percent power, I've got one hundred percent times of
Speaker 1: log of I've got one dB loss. So you can
Speaker 1: express it as a minus one divided by t, so
Speaker 1: i'd be ten one hundred percent times of log minus
Speaker 1: one of minus one divided by ten is minus point
Speaker 1: one seventy nine point four percent. So if I've got
Speaker 1: one hundred watts of power, and I've got one dB
Speaker 1: loss of my coats of my end of my through
Speaker 1: my transmission line, then I'm only going to get seventy
Speaker 1: nine point four watts out to the end to the antenna,
Speaker 1: So I've lost that power is all dissipated as heat
Speaker 1: in the feed in in the feed line. That's why
Speaker 1: it's really important when you're figuring out what coacts to
Speaker 1: choose or what to use. The transmission losses can be
Speaker 1: fairly high, especially at high at higher frequencies. So uh,
Speaker 1: twenty nine point six percent is lost in the feed line,
Speaker 1: so one hundred wats out, so one dB loss in
Speaker 1: your coaxs, you're losing twenty percent of your power. So
Speaker 1: current is the flow of electrons measure in amps. You
Speaker 1: remember that from your tech from your technician class. It's
Speaker 1: measured with an am meter. Voltage E is the force
Speaker 1: that it takes to make electrons move. It's measured in
Speaker 1: volts with a volt meter. Plarity of the voltage refers
Speaker 1: to the direction from positive or negative power. P is
Speaker 1: a product of voltage in current, It's measured in watts,
Speaker 1: So current's measured in amps, voltage in volts. Power in watts. Okay,
Speaker 1: so we're going to review our own's law. Here, Resistance
Speaker 1: is equal to voltage divided by current, current is equal
Speaker 1: to voltage divided by resistance, and voltage is equal to
Speaker 1: current time resistance. The voltage caused by a current flowing
Speaker 1: through a resistor is called voltage drop. Un let's review
Speaker 1: our frequency. A complete sequence of alternating current is when
Speaker 1: it starts at zero, reaches the peak, comes back through zero,
Speaker 1: has a negative, and comes back to the zero itself.
Speaker 1: That whole loop is a complete cycle. The number of
Speaker 1: cycles per second is a current frequency, and it's measured
Speaker 1: in hurts. And a harmonic is a frequency of of
Speaker 1: some integer multiple of the lowest fundamental frequency. A harmonic
Speaker 1: of twice the frequency is called the second harmonic, and
Speaker 1: three times called the third harmonic. So if you had
Speaker 1: a one megahurtz signal, second harmonic would be two megaherts,
Speaker 1: third harmonic would be three megahertz, and so on, and
Speaker 1: there's no such thing as the first harmonic. The first
Speaker 1: harmonic is the fundamental itself, would be one megahertz. The
Speaker 1: speed of light is three million meters per second three
Speaker 1: times ten to the eight, somewhat slower in wires and
Speaker 1: cables when it flows to a medium. The wavelength of
Speaker 1: radio is a distance it travels very one complete cycle,
Speaker 1: So wavelength is equal to the speed of light over
Speaker 1: the frequency. Frequency is the speed of light over the wavelength.
Speaker 1: Radio wave can be referred to by frequency or wavelength
Speaker 1: because of the speed of light constant, so sometimes you'll
Speaker 1: hear it talk about one megahertz or so many meters.
Speaker 1: We're going to talk about parallel and series and parallel circuits.
Speaker 1: A circuit is any complete path through which current can flow.
Speaker 1: It's called the circuit. A series circuit where you have
Speaker 1: two or more components are connected so that the same
Speaker 1: current flows through all the components. That's a series circuit.
Speaker 1: The same current flows a parallel circuit. The same voltage
Speaker 1: is across all the applied components, So series circuit current
Speaker 1: flows through all of the pieces. Parallel circuit voltage is
Speaker 1: the same. The current is split between the different components,
Speaker 1: but the voltage is the same. So remember our dB formulas.
Speaker 1: DB's equal the ten log of the power ratio or
Speaker 1: twenty log the voltage ratio. Comparing a measured power or
Speaker 1: voltage to a reference value. DB's equal to ten log
Speaker 1: of the power over the power reference or twenty log
Speaker 1: the voltage measured over the voltage reference. Positive DV values
Speaker 1: mean that the ratio is greater than one, or it's
Speaker 1: called gain. Negative dB values ratio of less than one
Speaker 1: is called loss or attenuation. So you'll hear we talked
Speaker 1: that we use dbs a lot in amateur radio, and
Speaker 1: you'll say plus's and verminus dB. That talks about either
Speaker 1: gain or loss. Okay, what dB change represents a factor
Speaker 1: of two increase or or or decrease in power. So
Speaker 1: remember we talked about a factor of two. When you
Speaker 1: double something, it's three dB, right, because remember that's a power.
Speaker 1: Ratio of two divided by one is two, and the
Speaker 1: log of two is actually three point is point three
Speaker 1: times ten. That's where you get the three dB, So
Speaker 1: factor of two. So we use factor of two a
Speaker 1: lot in amateurad and we talk about we've doubled the power.
Speaker 1: The power is divided by half. Well, that's a three
Speaker 1: dB change. So how many watts of electrical power is
Speaker 1: used for four hundred volts DC is applied to a
Speaker 1: four hundred zero load. We'll remember our own's law formula
Speaker 1: of If you're looking at power. It's power squared, which
Speaker 1: is four hundred square divided by eight hundred. So sixteen
Speaker 1: hundred divided by sixteen thousand divided by eight hundred homes
Speaker 1: would be two hundred watts. How many watts of electrical
Speaker 1: power used by a twelve volt light bulb that draws
Speaker 1: point two amps? Okay? So which formul we're going to
Speaker 1: use here? So we're trying to find power, and we
Speaker 1: know power is equal to voltage times current, so twelve
Speaker 1: times point two is going to give us two point
Speaker 1: four watts. All right, So you've got to remember your
Speaker 1: own law equation the relationships between power, voltage and current. Okay,
Speaker 1: So how many watts are asking for power are consumed
Speaker 1: when a current of seven milliampers flows through a twelve
Speaker 1: twelve hundred and fifty oh resistor? All right, So we're
Speaker 1: given a current in million amps, so we probably need
Speaker 1: to convert that to amps, So seven million amps is
Speaker 1: point zero zero seven amps. Remember power is equal to
Speaker 1: the current square times resistance, So if I square point
Speaker 1: seven and I multiply that times twelve hundred and fifty ohms,
Speaker 1: you're going to get about sixty one milliwatts, all right,
Speaker 1: So when you see this question on the test, it
Speaker 1: seems like it's a lot of complicated math. But it's
Speaker 1: zero point oh seven square times twelve fifty and it's
Speaker 1: gonna be in milli watts. I've got million ams and ohms,
Speaker 1: I'm gonna have a milli watt answer. So remember they
Speaker 1: give you sixty one million watts and sixty one watts. Well,
Speaker 1: it's not gonna be sixty one watts, so the answer
Speaker 1: is sixty one milli watts. Okay, what percentage of power
Speaker 1: loss is equivalent to a loss of one dB? Okay,
Speaker 1: so if you if you remember, it's twenty log of
Speaker 1: one dB, so this is gonna be about twenty uh
Speaker 1: twenty percent. So one dB loss is uh, about eighty
Speaker 1: percent of your of your power is gonna make it through,
Speaker 1: and twenty is gonna be lost. Remember three dB is half,
Speaker 1: so one DB's about a third of that, so twenty
Speaker 1: point six percent. Remember the power equation is equal to
Speaker 1: the voltage square divided by resistance for DC. However, what
Speaker 1: is the value of E for AC power? So for
Speaker 1: AC power, it's not peak, it's not average. It's called
Speaker 1: root means square r or RMS. So we're talking about AC. Now.
Speaker 1: We were talking about direct current a minute ago, batteries
Speaker 1: and resistors. Now we're talking about a C alternating current
Speaker 1: alternating power. If our if RMS voltage is used in
Speaker 1: the equations shown for calculating power, the result of the
Speaker 1: AC signal is the same as for an unvarying DC voltage. Okay,
Speaker 1: So the RMS for a sine wave is point seven
Speaker 1: zero seven times the sine waves peak voltage. And this
Speaker 1: picture here shows on a sine wave there's r MS,
Speaker 1: there's peak to peak, and there's peak and uh, those
Speaker 1: are related. They're they're they're related, and they're shown here
Speaker 1: on this chart. Uh what they're talking about, and it's
Speaker 1: it has to do with the with the with the
Speaker 1: percent of the power inside the at the wave form.
Speaker 1: Point seven h seven is the RMS or the average
Speaker 1: power of that signal. And all right, some of the
Speaker 1: eight form formulas that we use for voltage is voltage
Speaker 1: RMS is a point seven oh seven times the voltage
Speaker 1: peak peak to peak divided by two. The voltage peak
Speaker 1: is one point four times voltage RMS. Volts peak to
Speaker 1: peak is two point eight two eight volts times RMS.
Speaker 1: So these relationships, these formulas here are important to understand.
Speaker 1: Just something you're gonna have to sort of memorize and
Speaker 1: take a look at. Assign wave with the peak voltage
Speaker 1: of seventeen volts, for example, has an RMS voltage of
Speaker 1: twelve point five twelve twelve volts. You're gonna take the
Speaker 1: peak voltage seventeen multiply times point seven oh seven, it's
Speaker 1: twelve volts. RMS as sign wave with the peak voltage
Speaker 1: of one hundred volts would be a Remember it's a
Speaker 1: peak to peak voltage, so you go peak the peak
Speaker 1: divided by two, it's fifty volts peak times point seven
Speaker 1: oh seven, it's thirty thirty five point four volts RMS.
Speaker 1: Assign wave an RMS voltage of twelve or twenty volts
Speaker 1: has what peak the peak voltage value, So this one
Speaker 1: hundred and twenty volts is what's in your household ac here.
Speaker 1: So if you put it in the silloscope in the outlet,
Speaker 1: checked it out, it would be three hundred and thirty
Speaker 1: nine volts peak to peak. It's a pretty good sized signal,
Speaker 1: but it's one hundred and twenty volts RMS. All right,
Speaker 1: here's some definitions of measurement of peak envelope power. PEP
Speaker 1: stands for peak envelope power. It's the average power of
Speaker 1: one complete RF cycle at the peak of the signal's envelope,
Speaker 1: a convenient way of measuring the max power of amplitude
Speaker 1: modulated signals. However, this definition is confusing, and let's talk
Speaker 1: about it a little bit. PEP or peak envelope power,
Speaker 1: is the average power of one complete RF cycle at
Speaker 1: the peak of the signals envelope. PEP is used because
Speaker 1: it's a convenient way to measure or specify the maximum
Speaker 1: power of amplitude modulated signals. And here's an example of
Speaker 1: peak of what the peak envelope power is. To calculate
Speaker 1: average AC power, you need to know the load impedance
Speaker 1: and the RMS voltage measure. The r measure measure the
Speaker 1: RF voltage at the very peak of the modulated signals envelope.
Speaker 1: This is the peak envelope voltage has shown in the figure.
Speaker 1: Once the RF cycle is is identified, we calculate the
Speaker 1: average power over its complete duration. That's the red area
Speaker 1: in this figure. Note that we calculate the power in
Speaker 1: both the positive and negative half cycles, and the negative
Speaker 1: they don't cancel out because they're shown in this In
Speaker 1: this example, Uh, the peak envelope voltage is squared, making
Speaker 1: both of them positive. So uh, start by measuring the
Speaker 1: amplitude of the peak, usually in volts, that is the
Speaker 1: peak envelope the pev in the figure on the previous slide.
Speaker 1: Then applied the following formula. So you notice here you're
Speaker 1: looking for where's the peaks on this little slide right here, right? So, uh,
Speaker 1: this one is higher than these, So that's there. There's
Speaker 1: the peak on the pop positive, there's a peak on
Speaker 1: the negative. So those are the pulses you wanna you
Speaker 1: wanna figure out. So so when when when you're trying
Speaker 1: to say, what's my transmitted output power, it's gonna be
Speaker 1: when you're at the peaks. These smaller peaks take less
Speaker 1: power than the taller ones, right, So you're looking for
Speaker 1: the tallest peak envelope power, right, the peak voltage is there.
Speaker 1: Peak envelope power is equal to volt armis square divided
Speaker 1: by r. For an example, if we have fifty volts
Speaker 1: across a fifty ome load, the peak envelope power is
Speaker 1: fifty times zero point seven oh seven. To get the
Speaker 1: RMS value divided by the load gets twenty five watts.
Speaker 1: If a fifty load is dissipating twelve hundred watts pep,
Speaker 1: the RMS voltage is square root of the peak envelope power,
Speaker 1: which is twelve hundred times of resistance fifty homes two
Speaker 1: hundred and forty five volts. So these are these little formulas,
Speaker 1: these relationships. Is probably the most math you're gonna have
Speaker 1: to know for this general class license. It's not too bad.
Speaker 1: You just got to understand a few of them. If
Speaker 1: in a silloscope measures two hundredvolts peak to peak across
Speaker 1: a fifty home load, what would be the peak envelope power?
Speaker 1: All right, So we've got to take we've got peak
Speaker 1: to peak, right, So peak to peak RMS is point
Speaker 1: seven oh seven times the peak to peak divided by two,
Speaker 1: all right, that's where you get the RMS value. And
Speaker 1: then you're gonna divide that by the fifty on loads.
Speaker 1: So point seven seven times two hundred squared one hundred
Speaker 1: watts for the same device that five hundred volts peak
Speaker 1: to peak, the peak envelope power would be six hundred
Speaker 1: and twenty five watts. Okay, So one hundred wats six
Speaker 1: hundred and twenty five watts, So PP equals the average
Speaker 1: power if an amplitude modulated signal is not modulated. Okay.
Speaker 1: An example this one is when modulation is removed from
Speaker 1: the AM signal, leaving only the carrier, or when or
Speaker 1: when a CW transmitter is key. An FM signal is
Speaker 1: constant power signal, so PEP is always equal to the
Speaker 1: average power of an FM signal. In other words, if
Speaker 1: an average reading WAT meter connected to your transmitter reads
Speaker 1: one thousand and sixty watts, when you close the key
Speaker 1: on CW your PW, your PEP output power will be
Speaker 1: one thousand and sixty watts. Okay. So what is the
Speaker 1: PEP produced by two hundred volts the peak across a
Speaker 1: fifty O dummy load? Okay? So how would you do
Speaker 1: this one? Well, I guess I need to put that.
Speaker 1: Should have told you. So it's going to be peak
Speaker 1: envelope power two hundred watts peak to peak. So you
Speaker 1: got to convert that to peak. So two hundred divided
Speaker 1: by two divided by fifty is one hundred zermes. What
Speaker 1: value of an AC signal produces the same power dissipation
Speaker 1: and a resistor as a DC voltage of the same value. Okay,
Speaker 1: it's gonna be the RMS value because an AC signal,
Speaker 1: remember is peak to peak. But the RMS value is
Speaker 1: the point seven to seven. That's the equivalent of the
Speaker 1: DC power of the of the DC voltage. RMS is
Speaker 1: what you want to use. What is the peak to
Speaker 1: peak voltage of a sine wave when an RMS voltage
Speaker 1: of one hundred and twenty volts, so it's gonna be
Speaker 1: one hundred and twenty volts times one point four, which
Speaker 1: is gonna be around three hundred and thirty nine volts,
Speaker 1: I believe, yep. So this is what Again, if you
Speaker 1: measured the AC outlet at your house within ASILL scope,
Speaker 1: you'd see three hundred and thirty nine volts peak to peak.
Speaker 1: But what we're told it's one hundred and twenty volts.
Speaker 1: That's the r MESS value. Okay. The ARMISS value is
Speaker 1: what we normally characterize for the AC voltage at your house.
Speaker 1: What's the ARMIST voltage of a signed way with the
Speaker 1: value of seventeen volts peak? Okay, so it'll be seventeen
Speaker 1: times zero point seven, which will be around twelve volts.
Speaker 1: What's the ratio of a peak to peak average power
Speaker 1: of an unmodulated carrier. Okay, peak to peak to average,
Speaker 1: it's about points. Well, it'd be one peak to peak.
Speaker 1: Oh for the ratio of a peak to peak to
Speaker 1: average power of an unmodulated carrier is it's unmodulates. What's
Speaker 1: exactly the same. All right. Once you modulate it, then
Speaker 1: the power is going to get less point seven oh seven.
Speaker 1: But if it's unmodulated, all the powers is at the
Speaker 1: carrier itself, so it's one. The ratio is the same.
Speaker 1: What's the arm miss volt? Did you across a fifty
Speaker 1: zero load dissipating twelve hundred watts? Okay, so we're gonna
Speaker 1: say equals I R fifty divided by that's gonna be
Speaker 1: about twelve hundred uh divided by fifty that square met
Speaker 1: to that, it's gonna be about two hundred and fifty
Speaker 1: volts two hundred and forty five volts. What is the
Speaker 1: peak envelope power of an unmodulated care If the average
Speaker 1: power is one thousand and sixty watts, it's it's unmodulated,
Speaker 1: so it's gonna be one thousand and sixty watts. What's
Speaker 1: the peak envelope power of five hundred volts peak to
Speaker 1: peak across a fifty load about sixty peak to peak
Speaker 1: cross about six hundred, yeah, six hundred watts. Now we're
Speaker 1: gonna talk about some basic components. We're done with the
Speaker 1: math for a while. Three most basic components resistors. They're
Speaker 1: designated to have an R. They're used to resist the
Speaker 1: flow of electricity, and they're measured in omes. So resistance
Speaker 1: are omes. Capacitors usually shown designated with the letter C.
Speaker 1: They store electrical energy and they're measured in fare ads.
Speaker 1: Then inductors designated with L store magnetic energy measured in Henri's.
Speaker 1: So capacitors store electrical energy, inductor store magnetic energy, so
Speaker 1: omes fare ads and Henri's R, C and L. Typical
Speaker 1: values associated with components include the nominal value, the tolerance,
Speaker 1: temperature coefficient, and power rating. So if you go by
Speaker 1: a capacitor with a certain value like say one hundred
Speaker 1: microfarads or a hundred peokle fareds, it'll come with the
Speaker 1: tolerance nominal values one hundred peokle ferreeds, but has a
Speaker 1: tolerance plus or minus a certain amount temperature co efficient, How,
Speaker 1: what's the tolerance versus what's the capacity's over temperature and
Speaker 1: a power rating. Capacitors are volts, so those are typically
Speaker 1: the characteristics that describe the component that you're buying. Some
Speaker 1: schematic symbols. As you recall from the technician class, a
Speaker 1: schematic is as a paper drawing of electrical components connected together.
Speaker 1: And resistors have looked like the little squiggly line here,
Speaker 1: and there's different symbols for different types of resistors. These
Speaker 1: are the common ones. There's a fixed resistor, variable photo resistor,
Speaker 1: adjustable tact resistor, a theoristor. Capacitors show up on schematics
Speaker 1: look like this, and there's different kinds of capacitors, fixed
Speaker 1: and non polarized and polarized which we call electrolytic variable
Speaker 1: capacitors feed through. So this is how they be represented
Speaker 1: on electrical schematic. Remember, electrical schematic is how you hook
Speaker 1: interconnect these components together to form a circuit. An inductor
Speaker 1: symbol usually looks like this. Uh, there's air core, iron core. Uh,
Speaker 1: there's actually transformers. A variant of these fair eyed beads
Speaker 1: is an example of an inductor. So these are what
Speaker 1: the symbols look like. There's different kinds of tubes with
Speaker 1: different kinds of uh uh interface, different kinds of oh connections.
Speaker 1: There's they're they're they're like diodes. There's a triode, a pentode,
Speaker 1: and a cathod. It's how many uh uh this anodes
Speaker 1: and cathods do they have? And they come in different varieties,
Speaker 1: different sizes, different types for different functions and uh These
Speaker 1: are the symbols for tubes wiring. Again, when you have
Speaker 1: your electrical schematic and you've got wire shown on there,
Speaker 1: you can these are symbols for our wires connected? Are
Speaker 1: they not connected? Are there several wires that form like
Speaker 1: a data bus? Is it a ribbon cable? Multi cables?
Speaker 1: Is it a coaxial cable? These are ways to show
Speaker 1: common wiring symbols on the schematic. There are several common
Speaker 1: types of resistors that you can buy, and there's carbon film,
Speaker 1: metal film, wire around, adjustable thick film. And the resistors
Speaker 1: you buy are for different applications. You may have something
Speaker 1: that needs to be non magnetic or has less of
Speaker 1: an inductance, or you need something that's going to be
Speaker 1: a lot of power, like a load resistor. Resistors come
Speaker 1: a variable resistor like a potentiometer, so they come in
Speaker 1: different type shapes for different sizes and different power ratings,
Speaker 1: different tolerances. They come in nominal value sizes, usually between
Speaker 1: one ome and a meg ome. UH there's UH resistors
Speaker 1: I said come in different values like UH a hundred
Speaker 1: owned resistor, three hundred and thirty owned resistor. There's not
Speaker 1: a one hundred and forty three owned resistor that's made. UH.
Speaker 1: There're standard UH resistance values. So you if you're picking
Speaker 1: a resistor, you've got to pick the resistance that you
Speaker 1: need and then find the one that's closest to the
Speaker 1: value that you are trying to use. UH. Most common
Speaker 1: units they're omes killiomes and megomes. Usually for resistors, you
Speaker 1: don't usually see a tear uh terra own resistor or
Speaker 1: something like that. So UH ohmes are uh omes killiomes
Speaker 1: and megos are the standard sizes. The precision of resistors
Speaker 1: one percent up to ten percent, depending on the application
Speaker 1: that you have, UH how well you need to control
Speaker 1: the resistance. Sometimes the resistance needs to be controlled. Sometimes
Speaker 1: it really doesn't matter too much, depends on what you're doing.
Speaker 1: So if you've got a if you've got a a
Speaker 1: one killiome resistor, you divide by a thousand UH to
Speaker 1: get If you to get to convert from homes to
Speaker 1: killing homes, you divide by a thousand. Convert to megomes,
Speaker 1: you're gonna divide by a million. So sometimes you you've
Speaker 1: got to convert between the units. Sometimes you've got a
Speaker 1: mix of uh megomes and killiomes in the same circuit,
Speaker 1: and you want to put them into the same UH
Speaker 1: bands or conditions so you can do your multiplication in
Speaker 1: your math easier. So this is the way you would
Speaker 1: convert between the two. Example, if I had one hundred
Speaker 1: and fifty owned resistor, it's a point one five k
Speaker 1: divided by a thousand, or one hundred and fifty own
Speaker 1: resistor divide by a million to get two point oh
Speaker 1: meg homes. So if you're trying to convert between the two,
Speaker 1: this is the way you would you would do that,
Speaker 1: and the exam here's another example of a four point
Speaker 1: seven k own resistor. It's forty seven hundred homes or
Speaker 1: point oh four seven meg homes. So another example of
Speaker 1: I've got a megoon resistor how many homes is that
Speaker 1: it's a bunch twenty twos. Inductors come in different types
Speaker 1: there's the air, the air core which is just a
Speaker 1: y which is a winding of wire with air in
Speaker 1: the middle. Variable core that you can tune around with
Speaker 1: the US as a pickup up off the top. There's
Speaker 1: a magnetic core. Those are the common ones, like resistors
Speaker 1: double lines indicate a magnetic core. Veriable resistors like we
Speaker 1: use in your end, like used for and for antenna tuners.
Speaker 1: There's real small inductors you can put on circuit boards.
Speaker 1: Somebody's different shapes and sizes, different symbols for them. So
Speaker 1: member aductor stores magnetic energy. Its directionally proportional to the
Speaker 1: number of turns in the area that's enclosed in the inductor.
Speaker 1: Make an inductor longer without changing the number of turns
Speaker 1: or diameter reduces the inductance. Increasing the ability to store
Speaker 1: magnetic energy is called permeability, which increases the inductance. The
Speaker 1: type of core and windings effects inductance are very according
Speaker 1: to the use purpose of the inductor, so depending on
Speaker 1: what you're trying to make. UH variable inductors are often
Speaker 1: used in low power receiving transmitting applications, So we use
Speaker 1: those in UH to tune the i F frequency to
Speaker 1: UH tune across the band. You usually have a variable
Speaker 1: inductor adjusted and they're adjusted by moving the magnetic core
Speaker 1: in and out of the inductor. So usually when you're
Speaker 1: tuning a circuit building a filter module, you put an
Speaker 1: inductor in there and you and you'll it has a
Speaker 1: piece of uh coil with an inductor that you can
Speaker 1: move in and out to change the inductance. And that's
Speaker 1: how you tune that particular frequency. It's a it's a
Speaker 1: moving piece. Sometimes they're threaded. High power inductors are made
Speaker 1: by sliding the contact along the inductor itself. This is
Speaker 1: a lot of your your antenna tuners will have a
Speaker 1: roller inductor it's called in there and and a pickoff
Speaker 1: that rolls along as the inductor turns, that moves along
Speaker 1: pick off. The different values of the inductance, like the resistors,
Speaker 1: you can convert between micro Henri's, nano Henri's, and million Henri's.
Speaker 1: This is the typical values of those three hundred and
Speaker 1: thirty nano Henry is equal to zero point three to
Speaker 1: three micro henries and so on, So you can convert
Speaker 1: from micro henris to nano Henri's milli henries. You have
Speaker 1: to do this quite a bit when you're doing your calculations,
Speaker 1: you want to convert to one to the other so
Speaker 1: you're all the same. When you have two conductors that
Speaker 1: are close together, like this picture shows here, you have
Speaker 1: what's called induced in coupling, magnetic field from one conductor
Speaker 1: can pass through and get to the second one. UH.
Speaker 1: It's a way to share the energy between them. This
Speaker 1: is called coupling. The buildings of inductors to share or
Speaker 1: transfer magnetic energy is called mutual inductance. And sometimes this
Speaker 1: is what you want, sometimes you don't want. This depends
Speaker 1: on what your circuit is. So inductor design UH. In
Speaker 1: a toroid design like this picture is shown here, the
Speaker 1: the winding goes around a magnetic core and all the
Speaker 1: field is is is is maintained within the within the
Speaker 1: inductor itself. There's really not a large magnetic field outside
Speaker 1: the component itself, and this makes it handy when you're
Speaker 1: when you're doing on circuit board design. You can put
Speaker 1: a whole bunch of these wound around iron core pretty
Speaker 1: close together. There's not a lot of mutual inductance sharing.
Speaker 1: Composition of the cored varies. You can the cores themselves
Speaker 1: come and powdered fair eyes. There's different types of cores
Speaker 1: based on the range of frequency that you want to use.
Speaker 1: Some cores are better for high frequencies and low frequency,
Speaker 1: So depending on your application, you pick the core that's
Speaker 1: right for the fregency range that you want to use.
Speaker 1: Some of the core materials are exotic or have different types,
Speaker 1: they have different mixes to them, and so when you're
Speaker 1: trying to pick out a core in ham rate that
Speaker 1: we use, maybe a family of three or four different
Speaker 1: values for our frequency bands or HF VHF U h F,
Speaker 1: So usually find a mix. The usually have a number
Speaker 1: assigned to them for the core, and you'll go find
Speaker 1: that core and go buy that piece. And they come
Speaker 1: in different diameters and sizes based on the power and
Speaker 1: the fregency range that you're trying to use. Okay, in
Speaker 1: this schematic symbol here, which one of these represents a
Speaker 1: field effect transistor, which is something we haven't talked about yet,
Speaker 1: but we'll be getting to that here in just a minute.
Speaker 1: But the field effect transmitter is simple number. Uh, well
Speaker 1: it's actually simple number one here. That's this symbol right here.
Speaker 1: Field effect transistor looks like this, So, and what's a
Speaker 1: zener diode. We hadn't talked about that yet, but we will. Uh.
Speaker 1: It's this symbol right here, it's a diode. This is
Speaker 1: a diode symbol. A zener usually has a line like
Speaker 1: this on it cause it's uh it's it's gonna reverse
Speaker 1: diet bias to a certain voltage. So d uh. Which
Speaker 1: symbol here represents an N P N transistor. Uh, that's
Speaker 1: gonna be number two. You haven't talked about that. Uh.
Speaker 1: Which symbol represents a solid core transformer? Alright? Uh? Transformer
Speaker 1: looks like number six over here. And what's a tapped inductor?
Speaker 1: Remember the tapped inductor is This is an inductor and
Speaker 1: it's got a tap off of one of the windings.
Speaker 1: So it's a tapped inductor. That'd be number seven. And
Speaker 1: let's see which determines the performance of a fairiche core
Speaker 1: at different frequencies. Well, it's going to be the composition. Uh,
Speaker 1: it's going to determine the the performance at different frequencies. Uh.
Speaker 1: What's the advantage of using a fairite core over a
Speaker 1: toroidial coil core. If to use a fairite core, the
Speaker 1: magnetic properties will be optimized for a specific range magn
Speaker 1: use magnetic it's contained in the core. Large values of
Speaker 1: inductors may be may be obtained. I guess all those
Speaker 1: look pretty good to me. It is, all right. So
Speaker 1: talking about capacitors that have two conducting surfaces, it's called
Speaker 1: electrode and they're separated by a dielectric. Capacitance is measured
Speaker 1: in fare ads. It blocks DC current flow. And the
Speaker 1: simplest capacitors a pair of metal plates separated by air.
Speaker 1: You can increase the capacitates by increasing the surface area,
Speaker 1: or moving the surface closer together, or changing the dielectric materials.
Speaker 1: So there's three ways you can change the capacitates. And
Speaker 1: capacitors come in all different shaped sizes based on all
Speaker 1: those factors just talked about, the large surface area for
Speaker 1: larger capacitans, moving them plates closer together, putting different materials
Speaker 1: in them. All those things make up the different types
Speaker 1: of capacitors that we have. Tantalum and electrolytic capacitors are polarized.
Speaker 1: These are capacitors the DC voltage can only be applied
Speaker 1: in one direction without damaging the electrolyte that's inside, so
Speaker 1: very important when using an electrolytic or TANNELM capacitor that
Speaker 1: you've put it in your circuit the right playerity with
Speaker 1: the right voltage. Important to check that out. If you don't,
Speaker 1: things will usually get heat up and burn up. Capacitors
Speaker 1: have voltage ratings. Exceeding the ratings can cause an arcing
Speaker 1: between the conducting surfaces, usually destroys the capacitors, so make
Speaker 1: sure you've got the If you've got a tanelum or electrolytic,
Speaker 1: you've put the voltage on correctly, and then make sure
Speaker 1: that the voltage ratings that you're applied for the capacitor
Speaker 1: are not exceeded. Different types of capacitors Ceramic used a
Speaker 1: lot for RF filtering and bypassing of high frequencies. Fairly
Speaker 1: low costs probably the most common. Plastic film are used
Speaker 1: in audio circuits and lower radio frequencies. Silver miica they're
Speaker 1: highly stable, low loss used in RF circuits. Electrolytic and
Speaker 1: anilem usually use in power supply circuits because you usually
Speaker 1: want to get large capacitor values and those can accommodate
Speaker 1: that very large sized capacitor large capacitance values. Air and
Speaker 1: vacuum dielectric capacitors, those are usually good for transmitting and
Speaker 1: RF circuits. Capacitors are used to block. They can pass
Speaker 1: AC signals while blocking D six signals. They can bypass
Speaker 1: provide a low impedance path for AC signals around high
Speaker 1: impedance circuits. Used a lot in filtering for filterings itself
Speaker 1: to smooth out voltage pulses or rectified AC to even
Speaker 1: d C voltages, So capacitors used a lot to filter,
Speaker 1: especially in power supplies. Capacitors can also be used to
Speaker 1: absorb energy of voltage transients and spikes. UH tuning very
Speaker 1: frequency of resonance circuits are are you can by changing
Speaker 1: the capacity, you can change the resonance of a circuit
Speaker 1: and you can also ingust the impedance of certain circuits.
Speaker 1: So you'll see a lot of variable capacitors used in amplifier,
Speaker 1: in a in and antenna tuners. So talk specifically about
Speaker 1: aluminum and tanielum capacitors. They're designed to optimize their storage capabilities.
Speaker 1: The UH voltage must be applied within the correct plarity.
Speaker 1: These are plarity sensitive capacitors. They could come in large
Speaker 1: capacitans UH values UH. The aluminum uses a metal foil
Speaker 1: for conducting surfaces and dielectric as an insulating material layer
Speaker 1: on the foil created by a wet paste or jail,
Speaker 1: So they if you took them apart, there'd be a
Speaker 1: like a gel inside of them and their little foil.
Speaker 1: But they're available in super in large capacity values tannem
Speaker 1: similar to aluminum. That's porest materials. It's immersed in electroly
Speaker 1: like inside the capacitor itself. So what's the characteristic of
Speaker 1: an electrolytic capacitor high capacity value for given volume. So
Speaker 1: that's that's the big advantage of them low voltage cheramic capacitors.
Speaker 1: They're comparatively low cost. They're not uh yeah, low low costs.
Speaker 1: They're really they're not any of those other three. But
Speaker 1: they're just general purpose good capacitors for that, but they're cheap.
Speaker 1: Talk a little bit about transformers. Transformers uh uh can
Speaker 1: transfer ac power between two or more inductors UH through windings,
Speaker 1: and they share a common core. The windings UH two
Speaker 1: which power is applied is the primary. The winding from
Speaker 1: which the power is supplied is called the secondary. So
Speaker 1: a transformer has a primary and a secondary winding. The
Speaker 1: two in the frome. When voltage is applied to the
Speaker 1: primary winding, mutual inductance causes voltage to appear across the secondary,
Speaker 1: and the transformers work in both directions, either a step
Speaker 1: down or a step up transformer. So I can have
Speaker 1: a ten volts here, I want to take to two
Speaker 1: volts over here, or I can take two volts here
Speaker 1: and convert to ten up or down. Works both ways,
Speaker 1: So the transformers change power from one combination of AC
Speaker 1: voltage and current to another by using the windings with
Speaker 1: different turns a number of turns. There's a turns ratio
Speaker 1: the transformer occurs. The transformation occurs because all windings share
Speaker 1: the same magnetic field. They're wound on the same core.
Speaker 1: That's why they work like like they do. Significant change
Speaker 1: between secondary and primary using requires a change in wire
Speaker 1: size between the windings, sometimes because the amount of current
Speaker 1: and the amount of voltage that's being transferred. Sometimes you
Speaker 1: have to change the wire size for the appropriate wire
Speaker 1: gate size and a step up transformer. The primary carries
Speaker 1: higher current and is wound with larger diameter wigher than
Speaker 1: the secondary. The ratio of the number of turns in
Speaker 1: the primary winding, which is designated by NP, to the
Speaker 1: number of turns in the secondary, which is n s,
Speaker 1: determines how much current and voltage are changed. Since most
Speaker 1: circuits are connected with voltage, most transform equations relate primary
Speaker 1: voltage to secondary voltage, so they call it ep to es.
Speaker 1: Here's the relationship the number of secondary windings in primary.
Speaker 1: The number of the ratio between secondary voltage and primary
Speaker 1: voltage to secondary windings and primary windings is expressed in
Speaker 1: that relationship. There So the number of the voltage on
Speaker 1: the secondary is equal to the voltage on the primary
Speaker 1: time the ratio times the ratio of the windings used
Speaker 1: a lot. So what is the voltage across a fifteen
Speaker 1: hundred turn secondary winding if one hundred and twenty volts
Speaker 1: is applied across the primary winding. Well, we use our
Speaker 1: relationship here. We say one hundred and twenty volts times
Speaker 1: the number of secondary windings divided by the primary windings,
Speaker 1: which is three times one hundred and twenty so three
Speaker 1: hundred and sixty volts ac. So if I put in
Speaker 1: a one hundred and twenty volts AC with the transformer
Speaker 1: winding ratio of three to one, I get an increase
Speaker 1: of three on the secondary. So this is how I
Speaker 1: can This is a step up transformer one hundred and
Speaker 1: twenty volts in three hundred and sixty volts out, So
Speaker 1: what would be the secondary the primary transfer ratio and
Speaker 1: one hundred and fifteen volts to five hundred volt range. Well,
Speaker 1: you're gonna use the same thing here, the same ratios.
Speaker 1: You plug in your numbers and get five hundred over
Speaker 1: one hundred and fifteen, which is about four point three.
Speaker 1: So that would be the churns ratio. So if I
Speaker 1: wanted to change from one fifteen to five hundred, I
Speaker 1: would do a turns ratio of about four point three
Speaker 1: to get that. To murk, what happens if a signal
Speaker 1: is applied to the secondary winding of a four to
Speaker 1: one transformer instead of the primary. Well, a four to
Speaker 1: one transformer has four times a number of turns in
Speaker 1: the prim then the secondary, applying the signal to the
Speaker 1: secondary will increase this voltage proportionally four times the input voltage. Okay,
Speaker 1: So what causes a voltage to appear across the secondary
Speaker 1: winding of a transformer when an AC source is connected
Speaker 1: across its primary winding? Okay, it has to do with
Speaker 1: the mutual inductance. See all right, it's not capacitans. We're
Speaker 1: not talking about that it's mutual inductance. What is the
Speaker 1: output voltage of an input signal? What is the output
Speaker 1: vultage of an input signal is applied to the secondary
Speaker 1: winding of four to one step down transform instead of
Speaker 1: our primary winding, input voltage would be multiplied times four.
Speaker 1: Because this question is a little tricky. I got the
Speaker 1: input output four to one, and I put the I
Speaker 1: put it on the secondary side, so it's a step
Speaker 1: down transformer, but I put my voltage on the primary side,
Speaker 1: so it goes it's a step up transformer going the
Speaker 1: opposite direction. So you have to read the question understand.
Speaker 1: Our transformer can work both ways, and it's a four
Speaker 1: to one step down transformer design, but instead you put
Speaker 1: the you put it on the secondary winding, so it's
Speaker 1: it's multiplied by four. What's the primary winding wire of
Speaker 1: a voltage step up transformer? Why is it large? Usually
Speaker 1: larger than the secondary windings. It's to accommodate the higher
Speaker 1: current should be you change the wire side because of
Speaker 1: a current issue, so it's b What is the voltage
Speaker 1: output of a transformer with a five hundred turn primary
Speaker 1: fifteen hundred turn secondary with the one hundred and twenty
Speaker 1: volts AC applied. So this is a turns ratio of three.
Speaker 1: So it's gonna be an increase of UH. Let's see
Speaker 1: IPUT transformer five hundred tern primary UH three hundred and sixty.
Speaker 1: It's it's a three to one times times three. Al Right,
Speaker 1: Now we're gonna talk about circuits and primary UH, series
Speaker 1: and parallel circuits. So in a series circuit, UH, the
Speaker 1: current flows through all the all the components is the same,
Speaker 1: all right. In a parallel circuit, the voltage across all
Speaker 1: the components is the same. The current may vary, and
Speaker 1: the voltage on a series circuit varies between component. In
Speaker 1: a series circuit, the current is the same in all components,
Speaker 1: and voltage are summed. It's called Kirkoff's law. Voltages add
Speaker 1: in a series circuit. In parallel circuits, voltage across all
Speaker 1: components is the same, and the sum of the currents
Speaker 1: into and out of the circuit junctions must be equal.
Speaker 1: Kirkiff's current law. Currents add in a parallel circuit, So
Speaker 1: voltages add in a series circuit, currents add in a
Speaker 1: parallel circuit. Components connected in series or parallel can be
Speaker 1: replaced with a single equivalent component. So resistors so resistors.
Speaker 1: And if you have a bunch of resistors in series,
Speaker 1: you add the values. If you have a bunch of
Speaker 1: inductors in series, you add the values. If you have
Speaker 1: capacitors in series, you add. You take the reciprocal of
Speaker 1: the reciprocals that you add together. So we'll talk about
Speaker 1: that near in a second. And in parallel, resistors are
Speaker 1: reciprocals of reciprocals, and inductors are reciprocals of reciprocals, and
Speaker 1: capacitors you add the values. So let's talk about this
Speaker 1: a little bit. So I have a resistor and I
Speaker 1: add another resistor in series, I increase the resistance. If
Speaker 1: I add a resistor in parallel, I decrease, and the
Speaker 1: same foreign inductor. If I add another inductor, I increase.
Speaker 1: So if I had a one Microhenry deductor and I
Speaker 1: added a one micro Henry, i'd have two microhenrs. And
Speaker 1: if I add a capacitor in series with another capacitor,
Speaker 1: I get one over the reciprocal, so it decreases, and
Speaker 1: then the opposite if you parallel them. Here's an example
Speaker 1: talks about that. So if I have a resistor and
Speaker 1: I add some more resistors. The total resistance of this
Speaker 1: circuit is the sum of all those. If I put
Speaker 1: them in parallel, then the resistance is equivalent to the
Speaker 1: reciprocal of the reciprocal of the resistance of the resistors.
Speaker 1: So let's say I have one ome resistors here, this
Speaker 1: would be three omes. Okay, If these are one omed resistors,
Speaker 1: this is gonna be one over three, one over three,
Speaker 1: this is gonna be about one. Oh. So in capacitors,
Speaker 1: if I put them in series, it's the reciprocal of
Speaker 1: the reciprocals. If I have them in parallel, it's the
Speaker 1: sum of the capacitors and inductors. Like resistors, they're in
Speaker 1: a series. You add up the inductance that they're in
Speaker 1: parallel the reciprocals of them. Just something you gotta learn.
Speaker 1: And uh and remember let's talk about these, right, So
Speaker 1: three one hundred home three one hundred own resistors in
Speaker 1: series would be three hundred homes. In parallel, they'd be
Speaker 1: thirty three point three homes or one over the reciprocal.
Speaker 1: So if they're all the same values and they're in parallel,
Speaker 1: you can divide the value by the number of components.
Speaker 1: You have three one hundred microferreed capacitors would be three
Speaker 1: thirty three point three microfered and series and three hundred
Speaker 1: microfer and parallel. Okay, so resistors and capacitors the way
Speaker 1: they behave in series and parallel combinations are the opposite,
Speaker 1: but only two components. When you have only two components,
Speaker 1: the reciprocal calculation is greatly simplified. You can just when
Speaker 1: there's you know, so you can multiply. When you have
Speaker 1: only two components, you can multiply the two together and
Speaker 1: divide by the sum. So if I have one hundred
Speaker 1: omeen or two hundred zero resistor, you can multiply one
Speaker 1: hundred times two hundred divided by the sum. So that
Speaker 1: it's pretty pretty easy way if you just have two
Speaker 1: components without having to do all the reciprocal things. Inductance
Speaker 1: of a twenty million of a twenty mili henrys and
Speaker 1: fifty mili henry and in inductors you just in series
Speaker 1: you add them together. In parallel, you could add them
Speaker 1: divide by the sum. So twenty times five one hundred
Speaker 1: divided by seventy fourteen point twenty nine milli hendryes. So
Speaker 1: what's the total inductance of three ten milli henry inductors
Speaker 1: in parallel. Well, one over the sums, one over the
Speaker 1: recip it's the reciprocal of the reciprocals. And what's the
Speaker 1: total inductance of three ten milli henrys in series. You're
Speaker 1: gonna add them up thirty milli hendrys. What's the total
Speaker 1: capacititans of two five nano fareds and one seventy seven
Speaker 1: to fifty pico faired in series. Okay, so they're in series,
Speaker 1: so you're gonna take You're gonna first of all, convert
Speaker 1: them all to piko fairgs, is what I would do.
Speaker 1: So by five nano fareds tomes of thousands is five
Speaker 1: piko fareds. So now I've got an equation looks like
Speaker 1: one over the reciprocals, one over five thousand plus one
Speaker 1: over five thousand plus one over seven fifty reciprocal of reciprocals,
Speaker 1: you get equivalent to five hundred and seventy seven piko fareds.
Speaker 1: So this is a case where you you'd want to
Speaker 1: convert all to the similar units. You could either have
Speaker 1: done all nano fares or all pickol fareds. In this
Speaker 1: case I think was easier to convert to piko farads,
Speaker 1: and then once you get them through the same units,
Speaker 1: then you can do your reciprocal calculation. And in parallel
Speaker 1: you would add them up, but again you want to
Speaker 1: make sure you convert them all to the right unit.
Speaker 1: And we get ten gets ten seven hundred and fifty
Speaker 1: piceal fares or ten point seven five nano fads. Okay.
Speaker 1: So how does the total current relate to the circuits?
Speaker 1: To individual circuits and a circuit and of parallel resistors,
Speaker 1: So parallel resistors, the current is gonna let's see, it
Speaker 1: decreases as more parallel branches are added to the circuit.
Speaker 1: I think that's b B. It equals the sum of
Speaker 1: the currents through each branch. That's that's the Kirkoff law,
Speaker 1: that's right. What is the total resistance of a ten
Speaker 1: and twenty and fifty er resistor connected in parallel? Okay?
Speaker 1: So you've got to add one over ten plus one
Speaker 1: over twenty plus one over fifty add those together, add
Speaker 1: them back up, and let's see. I think I've got those.
Speaker 1: Let's see, that's gonna be five point nine ms. Okay,
Speaker 1: And what is the approximate total resistance of one hundred
Speaker 1: and two hundred OW resistor in parallel. It's gonna be
Speaker 1: h one over one over two hundred plus one over
Speaker 1: one over two hundred, which is one over point zero
Speaker 1: one five, which is about sixty six point six owns
Speaker 1: or sixty seven homes. Okay, what is the equivalent capacities
Speaker 1: of two five nano fared capacitors and one seven and
Speaker 1: fifty po fared capacitor? Again, you wanna convert the nano
Speaker 1: fared capacitor uh to pico fareds and then UH at
Speaker 1: them together and it comes out to be uh ten
Speaker 1: points seventy five nano faired d Kay if I've got
Speaker 1: capacits of three one hundred micro fared capacitors connected in series.
Speaker 1: So if they're connected in series, it's one over the
Speaker 1: sum of the reciprocals. Uh, these are hundred micro fareds,
Speaker 1: so uh one over a hundred is point oh one,
Speaker 1: and you're gonna have three of those. It's gonna have
Speaker 1: one over point oh three, which is about thirty three
Speaker 1: point three micro fareds. All right, what's inductance of three
Speaker 1: ten military inductors connected in parallel? Again, you've gotta do
Speaker 1: one over the reciprocal of them, So it's gonna be
Speaker 1: one over point three or about three point three milli henrys.
Speaker 1: And what is inductance of twenty milli henry inductor connected
Speaker 1: in series with a fifty mili henry inductor. You're gonna
Speaker 1: just add them together, should get about seventy mili henrys.
Speaker 1: And the twenty microferreed capacitor connected in series with the
Speaker 1: fifty microfared capacitor, it's gonna be one over the two
Speaker 1: because it's gonna be one over twenty plus one over
Speaker 1: fifty one Over that, it's gonna be about one over
Speaker 1: point oh seven, which is about fourteen point three microfereds.
Speaker 1: And what's the following components? Which of the following components
Speaker 1: should be added to a capacitor to increase the capacitance?
Speaker 1: So if you want to increase the capacitance of a capacitor,
Speaker 1: you want to add it in in parallel, all right,
Speaker 1: ce capacitor in parallel. Which of the following components should
Speaker 1: be added to an inductor to increase the inductance? You're
Speaker 1: going to add an inductor in series D. And that's
Speaker 1: the end of that chapter right now.