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ATT TEST 5 NEWEST TEST 2025 | ALL QUESTIONS
AND CORRECT ANSWERS | GRADED A+ | LATEST
TEST | VERIFIED ANSWERS
Which class of amp is more efficient than class A and has higher fidelity than class B? ---------CORRECT ANSWER-----------------Class AB Which class of amp has the best efficiency but worst fidelity? --------- CORRECT ANSWER-----------------Class C What is DC bias at for class C amp? ---------CORRECT ANSWER------------- ----BELOW cutoff Collector current flows for how much of input signal (Class C amp)? --------- CORRECT ANSWER-----------------25% What amp configuration has the best values and is most commonly used? - --------CORRECT ANSWER-----------------Common emitter Which is the only amp configuration to INVERT the output signal? --------- CORRECT ANSWER-----------------Common emitter Which amp configuration is used to drive current? ---------CORRECT ANSWER-----------------Common collector
Which amp configuration has large voltage gain? ---------CORRECT ANSWER-----------------common base In common emitter amps, small inputs control what type of outputs? --------- CORRECT ANSWER-----------------Large, inverted outputs Which components establish base bias in common emitter circuit? --------- CORRECT ANSWER-----------------R1 and R Which components provide self biasing in common emitter circuit? --------- CORRECT ANSWER-----------------R4 and C C1 and C2 input/output coupling capacitors do what in common emitter circuits? ---------CORRECT ANSWER-----------------Pass AC and block DC A transistor at cutoff bias acts like what? ---------CORRECT ANSWER--------
What is DC bias for a Class A amp? ---------CORRECT ANSWER------------- ----ABOVE cutoff (like AB) What is the purpose of cascade (multistage) amps? ---------CORRECT ANSWER-----------------To increase gain
What is the effect on LOW frequency in RC coupled amps? Are individual stages affected? ---------CORRECT ANSWER-----------------Low frequency decreases total gain but individual stages are NOT affected What happens if frequency is too HIGH in RC coupled amps? --------- CORRECT ANSWER-----------------Reduces total gain What happens if Vpp is too LARGE in RC coupled amps? Are individual stages affected? ---------CORRECT ANSWER-----------------Output is distorted due to clipping and total gain is reduced. Stage gains are LOW What is the purpose of diode limiters? ---------CORRECT ANSWER----------- ------to limit the amplitude of input signal When does limiting occur in a series limiter? ---------CORRECT ANSWER--- --------------When the diode is reverse biased What type of signal reverse biases a series negative limiter? --------- CORRECT ANSWER-----------------Negative signals When does limiting occur in parallel limiters? ---------CORRECT ANSWER-- ---------------When diode is forward biased
What happens when circuit bias is added to limiter circuits? --------- CORRECT ANSWER-----------------partial alterations are eliminated by raising/lowering limits from 0V What is the purpose of diode clampers? ---------CORRECT ANSWER-------- ---------To clamp AC signal AT a DC output level What three components make up clamper circuit? ---------CORRECT ANSWER-----------------capacitor, resistor, diode When is the capacitor able to quickly charge in clamper circuit? --------- CORRECT ANSWER-----------------When the diode is forward biased (low resistance) What is the purpose of transistors? ---------CORRECT ANSWER--------------- --to control currents (signals) The emitter to base is always (forward/reverse) biased? ---------CORRECT ANSWER-----------------Forward (low ohms) The collector to base is always (forward/reverse) biased? --------- CORRECT ANSWER-----------------Reverse (high ohms) Which part of a transistor is heavily doped? ---------CORRECT ANSWER---- -------------Emitter
When saturated the transistor acts like a what? ---------CORRECT ANSWER-----------------Short What is cutoff bias? ---------CORRECT ANSWER-----------------The point where base bias reverse biases the emitter base junction stopping base current and collector current Alpha should never exceed what value? ---------CORRECT ANSWER-------- --------- 1 Beta should be around what values? ---------CORRECT ANSWER------------- ---- 20 - 400 Three types of bias circuits? ---------CORRECT ANSWER----------------- Fixed, self, combination What is the disadvantage of fixed biasing? ---------CORRECT ANSWER----- ------------Temperature sensative What are an advantage and disadvantage of self biasing? --------- CORRECT ANSWER-----------------Fixes temperature issues but lowers beta
Which type of biasing includes a voltage divider? ---------CORRECT ANSWER-----------------Combination How many classes of amps are there? ---------CORRECT ANSWER---------- ------- 4 Collector current in class A amps flows for how much of input signal? --------
- CORRECT ANSWER-----------------100% Which class of amp has the best fidelity and low distortion? --------- CORRECT ANSWER-----------------Class A What is DC bias for a class B amp? ---------CORRECT ANSWER-------------- ---At cutoff (0.6V) Collector current flows for how much of input signal (Class B amp)? --------- CORRECT ANSWER-----------------50% What is DC bias for class AB amp? ---------CORRECT ANSWER-------------- ---ABOVE cutoff Collector current flows for how much of input signal (class AB amp)? --------
- CORRECT ANSWER-----------------75%
When are DC bias voltage measurements taken when troubleshooting a multistage amp? ---------CORRECT ANSWER-----------------After faulty stage is found What type of measurements identify faulty components? ---------CORRECT ANSWER-----------------Resistance MOST faults in multistage amps cause what? ---------CORRECT ANSWER- ----------------Change in DC bias levels What are common faults in multistage amps? (4) ---------CORRECT ANSWER-----------------Failed transistor, opens, shorts, changed value Which coupling method has NO reactive components? ---------CORRECT ANSWER-----------------Direct What are push pull amps used for? ---------CORRECT ANSWER--------------- --Power amplification What is a disadvantage of common emitter push pull amps? --------- CORRECT ANSWER-----------------Expensive due to transformers, needs more room What is a general Av gain for common collectors? ---------CORRECT ANSWER-----------------Av = 1
What is the base connected to in fixed biasing? ---------CORRECT ANSWER-----------------Vcc What does the tab indicate on transistors? ---------CORRECT ANSWER-----
Transistor amplifiers require what type of signal to function? --------- CORRECT ANSWER-----------------DC bias and AC input signals What changes are necessary for amplification to occur? ---------CORRECT ANSWER-----------------Small change in base voltage, large change in collector current What amplifier has the best fidelity? ---------CORRECT ANSWER-------------- ---class A What amplifier has the best efficiency? ---------CORRECT ANSWER---------- -------class C When an input is applied across the emitter to base PN Junction, what is the relative resistance? ---------CORRECT ANSWER-----------------low
The suppressor grid reduces the effects of? ---------CORRECT ANSWER--- --------------secondary emission How many electrodes does a pentode have? ---------CORRECT ANSWER-- --------------- 5 What electron-tube amplifier configurations provides a 180 degrees phase shift from the input to the output? ---------CORRECT ANSWER----------------- common cathode What component supplies the electrons for the electron beam? --------- CORRECT ANSWER-----------------cathode What term is used to describe screens that produce only one color? --------- CORRECT ANSWER-----------------monochrome The _________ coating returns the secondary electrons to the power supply. ---------CORRECT ANSWER-----------------aquadag The set of coils which produces a vertical magnetic field is used to deflect the beam? ---------CORRECT ANSWER-----------------horizontally What happens in a transistor when the saturation point is reached? --------- CORRECT ANSWER-----------------Ic stops increasing
What happens in a transistor when the base voltage reverse biases the emitter to base PN junction? ---------CORRECT ANSWER----------------- cutoff occurs _______ is the ratio of Ic/Ie ---------CORRECT ANSWER-----------------Alpha What are the two names of the electrodes in an electron tube diode? --------
- CORRECT ANSWER-----------------plate and cathode How many electrodes does a tetrode have? ---------CORRECT ANSWER--- -------------- 4 When voltage is first applied to a gas filled tube, the gas will: --------- CORRECT ANSWER-----------------oppose current flow A negative potential with respect to the cathode on the control grid will: ----- ----CORRECT ANSWER-----------------repel electrons What component replaced the triode as an amplifier during the solid state revolution? ---------CORRECT ANSWER-----------------transistor The capacitor in a clamper circuit has a fast charge path when the diode is ___________ ---------CORRECT ANSWER-----------------forward biased
In a _____________ amplifier, when the base voltage increases~ the emitter current increases. ---------CORRECT ANSWER----------------- common collector In a _____________ amplifier, when base voltage decreases~ output voltage decreases. ---------CORRECT ANSWER-----------------common collector In a _____________ amplifier, when the emitter voltage increases~ the emitter to base forward bias decreases. ---------CORRECT ANSWER--------- --------common base In a ____________ amplifier, when the emitter voltage increases~ the emitter current decreases. ---------CORRECT ANSWER----------------- common base What type of coupling has the least effect on the collector AC signal for high frequency inputs? ---------CORRECT ANSWER-----------------LC coupling The ____________ amplifier output is controlled by a small input signal. ---- -----CORRECT ANSWER-----------------common emitter What type of output signal is produced by a class C common base amplifier? ---------CORRECT ANSWER-----------------amplified and inverted
In a RC coupled transistor amplifier, what is the result of a low frequency input signal? Stage gains ______, total gain ______, output signal _________ ---------CORRECT ANSWER-----------------good, low, undistorted In a RC coupled transistor amplifier, what is the result of a high VPP input signal? Stage gains ______, total gain ______, output signal _________ --- ------CORRECT ANSWER-----------------low, low, distorted What type of transistors are used in a common collector push-pull amplifier? ---------CORRECT ANSWER-----------------one NPN and one PNP In RC coupled amplifiers, normal operation is verified by comparing measured and calculated: ---------CORRECT ANSWER-----------------total current voltage gain The transistor bias _______________ are made after the faulty stage has been identified ---------CORRECT ANSWER-----------------voltage measurements The common emitter output phase is _____ degrees out of phase --------- CORRECT ANSWER----------------- 180 What class of amplifiers are biased so collector current is zero for half of the input signal? ---------CORRECT ANSWER-----------------class B
