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CET Associate Certified Electronics
Technician CIE book Questions and
Answers 100% Pass
Three Colors for a 10 ohm resistor
Brown Black Brown
Three Colors for 4.7 ohm resistor
Yellow Violet Gold
Two Terminal current control circuit device
rheostat
12 Volt battery across red red red resistor, mW dissipated by resistor
.65.5 mW
Resistance Equivalency formula
R1 x R2/R1+R
The larger the capacitor, the smaller/larger the voltage drop
smaller
Most common use of capacitors is to store ___________
energy
When plates of a series -resonant tuning circuit are moved closer together, the resonant frequency of the turned circuit increase/decrease
decrease. Moving plates closer together increases capacitance which decreases the resonant frequency fc= 1/2π√LC
True or False, the purpose of a 0.01 μF capacitor in parallel with a filter capacitor is to increase the capacitance
False, it is to offer a low reactance path to high frequency transients
A 0.05 μF capacitor is connected in series with a 0.08 μF capacitor. The series circuit has a capacitance of
.05x.08/.05+.08 μF = .031 μF
Inductors store energy in the form of a ___________ field
electromagnetic field
To prevent electrostatic coupling between the primary and secondary windings, power transformers are sometimes equipped with a ____________ shield
Faraday shield
The dot notation on a transformer tells which points are (in phase)(equal to current)
in phase
Name two types of transformers that can be used as preregulators
ferroresonant and self saturating
T=L/R
In a conventional JFET amplifier circuit, the input signal is at the ______ and the output is at the
gate, drain
The emitter resisitor in a conventional bipolar amplifier circuit is used for ___
temperature compensation
Why is a resistor always connected in series with an LED?
to protect the LED from high current
A series RC circuit is connected to a 20-V battery. How long will it take the capacitor to charge to 12.6 V if R = 10 K Ω and C = .08 μF
8 ms
name the 9 resistor colors in order 0 - 9
black brown red orange yellow green blue violet gray white
3:resistors in parallel, br bl au, r,r,au or, or au what is value?
1.0 and 2.2 and 3.3. GT= 1/1+1/2.2+1/3.3 = 1.7575. 1/1.7575 =.
what's the conductance GT of this parallel circuit
1.75 mhos
A lamp is rated 12 volts and .5 Watts when a 6 volt battery is connected across it how brightly will it glow?
18 watts or 1/4 rated brightness of 72 watts. remember P= E^2/R
Two lamps are to be connected in series lamp#1 12V 0.25 A lamp#2 12V .125A. which lamp should be connected in parallel with a resistor?
lamp 2
how many ohms should resistor be?
96 ohms. derive resistance from power law and ohms law
What is the RMS value of a pure sine wave current with an average value of 7.5 A
8.3 A. RMS to average value is .707/.636 = 1.11 times 7.5 = 8.3 A
In a series tuned circuit, increasing the capacitance will increase/decrease the resonant frequency
decrease
write the equation for a the resonant frequency of a series resonant circuit
1/2π√RC
write the equation for the resonant frequency of a parallel resonant circuit
1/2π√RC
increasing the resistance of a resistor that's connected across a parallel LC circuit will produce a (broader)(narrower) response curve
narrower. in a parallel circuit you are increasing the Q
can you affect resonant frequency in a low Q circuit by increasing the resistance?
yes
the total current flows through the base/collector/emitter
emitter IE=IB+IC
when a transistor is operated Class B--
the transistor is cut off in the absence of an input signal
increasing the capacity of the capacitor in a UJT circuit will increase/decrease the frequency of it's operation
decrease
device that imitates parallel SCR's
triac
the intrinsic standoff ratio is adjustable in a device called
PUT programmable unijunction transistor. the break over point is adjusted by setting the intrinsic standoff ratio
the totem pole/Darlington amplifier uses both PNP and NPN transistors
totem pole
what type of amplifier is called a beta squared amplifier?
Darlington
in a certain operational amplifier circuit, the feedback resistor is 15k ohms and the input resistor is 5k ohms. what's the gain of the amplifier if the signal is applied to inverting input?
-r2/r1 -15k/5k = -
definition of a Class A amplifier
A Class A power amplifier is one in which the output current flows for the entire cycle of the AC input supply. Hence the complete signal present at the input is amplified at the output.
in a Class A amplifier, what should the ratio of applied voltage to collector voltage?
collector voltage is half of applied voltage in Class A amplifier
quick test method for a Class A amplifier
connect voltmeter from collector to ground and short circuit emitter to base junction. transistor no longer conducts, and voltage at collector will equal applied voltage
equation to determine the bandwidth of frequency response with the square wave test
bandwidth= 0.35/rise time
square wave input to amplifier with excessive high frequency response, amplifier is ringing
what kind of distortion to the square wave is caused by problems with low frequency response?
distortions in the horizontal or flat side of the square wave form
prescaler
to view two waveforms simultaneously on an oscilloscope you use
an electronic switch
equation for the time constant of a series RL circuit
T=L/R
What is the equation for transistor current
Ic + Ib = Ie
Value of generator voltage when 3V across a resistor and 3V across a capacitor
4.2 (RMS)
In a parallel turned circuit, what affect will a change in resistance R have on resonant frequency and bandwidth?
It will change the resonant frequency and bandwidth?
Which component besides a zener diode operates with a reverse voltage?
varactor diode
What component is a protector against excessive voltage?
VDR
what's the impedance of a series rc circuit with a 10ohm XC capacitor and 10 ohm resistance?
14.14 ohms
what besides a zener diode operates with a reverse bias?
varactor diode
You'd expect to see a current source used in a
Differential amplifier
What is the equivalent of parallel SCR's?
triac
What is the gain-bandwidth product for a transistor?
it's a frequency value
In an oscillator circuit, what kind of waveform is at variable resistor?
sawtooth wave
If the power lione frequency is Hz, what is the ripple frequency of a bridge rectifier?
120 Hz
The output signal is 180° out of phase with the input in the
Common source circuit
What common configuration in a transmitter has a high input impedance and low output impedance?
collector current divided by base current
In a transistor amplifer, the gain can be increased by
in some cases increasing the base current, in some cases decreasing the base current
