ATT Test 5 (Latest 2024/ 2025 Update) Questions and Verified Answers| 100% Correct| Grade A

ATT Test 5 (Latest 2024/ 2025 Update)
Questions and Verified Answers| 100%
Correct| Grade A
Q: What is the purpose of diode clampers?
Answer:
To clamp AC signal AT a DC output level
Q: What three components make up clamper circuit?
Answer:
capacitor, resistor, diode
Q: When is the capacitor able to quickly charge in clamper circuit?
Answer:
When the diode is forward biased (low resistance)
Q: What is the purpose of transistors?
Answer:
to control currents (signals)
Q: The emitter to base is always (forward/reverse) biased?
Answer:
Forward (low ohms)

Q: The collector to base is always (forward/reverse) biased?
Answer:
Reverse (high ohms)
Q: Which part of a transistor is heavily doped?
Answer:
Emitter
Q: Which part of a transistor is lightly doped and thin? Does it allow current carriers to pass?
Answer:
Base. Allows most current carriers to pass
Q: Which part of the transistor is moderately doped?
Answer:
Collector
Q: Which part of the transistor is the largest to dissipate the most heat?
Answer:
Collector
Q: What allows the transistor to operate?
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What is the purpose of diode limiters? to limit the amplitude of input signal
When does limiting occur in a series limiter? When the diode is reverse biased
What type of signal reverse biases a series negative limiter? Negative signals
When does limiting occur in parallel limiters? When diode is forward biased
What happens when circuit bias is added to limiter circuits? partial alterations are eliminated by raising/lowering limits from 0V
What is the purpose of diode clampers? To clamp AC signal AT a DC output level
What three components make up clamper circuit? capacitor, resistor, diode
When is the capacitor able to quickly charge in clamper circuit? When the diode is forward biased (low resistance)
What is the purpose of transistors? to control currents (signals)
The emitter to base is always (forward/reverse) biased? Forward (low ohms)
The collector to base is always (forward/reverse) biased? Reverse (high ohms)
Which part of a transistor is heavily doped? Emitter
Which part of a transistor is lightly doped and thin? Does it allow current carriers to pass? Base. Allows most current carriers to pass
Which part of the transistor is moderately doped? Collector
Which part of the transistor is the largest to dissipate the most heat? Collector
What allows the transistor to operate? DC voltages (bias)
Collector current is (less than/greater than) base current greater than
What voltage is needed to forward bias the base to emitter? 0.6 V
The arrow of a transistor always points to what? Negative terminal (N-type material)
What is saturation bias? The point where increasing base voltage no longer increases collector current
When saturated the transistor acts like a what? Short
What is cutoff bias? The point where base bias reverse biases the emitter base junction stopping base current and collector current
Alpha should never exceed what value? 1
Beta should be around what values? 20-400
Three types of bias circuits? Fixed, self, combination
What is the disadvantage of fixed biasing? Temperature sensative
What are an advantage and disadvantage of self biasing? Fixes temperature issues but lowers beta
Which type of biasing includes a voltage divider? Combination
How many classes of amps are there? 4
Collector current in class A amps flows for how much of input signal? 100%
Which class of amp has the best fidelity and low distortion? Class A
What is DC bias for a class B amp? At cutoff (0.6V)
Collector current flows for how much of input signal (Class B amp)? 50%
What is DC bias for class AB amp? ABOVE cutoff
Collector current flows for how much of input signal (class AB amp)? 75%
Which class of amp is more efficient than class A and has higher fidelity than class B? Class AB
Which class of amp has the best efficiency but worst fidelity? Class C
What is DC bias at for class C amp? BELOW cutoff
Collector current flows for how much of input signal (Class C amp)? 25%
What amp configuration has the best values and is most commonly used? Common emitter
Which is the only amp configuration to INVERT the output signal? Common emitter
Which amp configuration is used to drive current? Common collector
Which amp configuration has large voltage gain? common base
In common emitter amps, small inputs control what type of outputs? Large, inverted outputs
Which components establish base bias in common emitter circuit? R1 and R2
Which components provide self biasing in common emitter circuit? R4 and C1
C1 and C2 input/output coupling capacitors do what in common emitter circuits? Pass AC and block DC
A transistor at cutoff bias acts like what?
What is DC bias for a Class A amp? ABOVE cutoff (like AB)
What is the purpose of cascade (multistage) amps? To increase gain
What are 4 types of coupling methods for multistage amps? RC, LC, Transformer, Direct
What is the most common coupling method for cascade amps? RC
What is a disadvantage of RC coupling? Low frequency response
Which coupling method has the least effect on collector AC signal? LC
When is transformer coupling used for multistage amps? When you want to amplify only a select frequency
What is a disadvantage of direct coupling? amplifies any signal, AC or DC, including unwanted signals
How is normal operation verified in RC coupled amps? Comparing TOTAL measured and calculated voltage gains
Does gain (Av) increase or decrease when loaded? Decreases (due to parallel resistances)
What is the effect on LOW frequency in RC coupled amps? Are individual stages affected? Low frequency decreases total gain but individual stages are NOT affected
What happens if frequency is too HIGH in RC coupled amps? Reduces total gain
What happens if Vpp is too LARGE in RC coupled amps? Are individual stages affected? Output is distorted due to clipping and total gain is reduced. Stage gains are LOW
Why are push pull amps used as final stage in multistage amps? Used to drive low resistive loads
What are 4 qualities of push pull amps? (two highs and two lows) HIGH current gain, HIGH efficiency, low output resistance, low distortion
Are transistors in series or parallel in a common emitter push pull amp? Parallel
What is the purpose of T1 in common emitter push pull amp? T1 develops input signals for Q1/Q2 that are 180 degrees out of phase
The output of a common emitter push pull amp is (in phase with/inverted from) the input? Inverted and amplified
What type of transistors does a common collector push pull amp use? One PNP and one NPN
Is the output of a common collector inverted or in phase with the input? In phase with
When are DC bias voltage measurements taken when troubleshooting a multistage amp? After faulty stage is found
What type of measurements identify faulty components? Resistance
MOST faults in multistage amps cause what? Change in DC bias levels
What are common faults in multistage amps? (4) Failed transistor, opens, shorts, changed value
Which coupling method has NO reactive components? Direct
What are push pull amps used for? Power amplification
What is a disadvantage of common emitter push pull amps? Expensive due to transformers, needs more room
What is a general Av gain for common collectors? Av = 1
What is the base connected to in fixed biasing? Vcc
What does the tab indicate on transistors?