Regulators, Transistors, and Oscillators

In amplifier classification, which class provides the best fidelity but lowest efficiency?

Class A

During alternator troubleshooting, if the unit fails to build up voltage, the technician should:

Verify the voltmeter and check wiring, brushes, and drive before flashing the field

Why is static electricity particularly harmful to JFETs and MOSFETs?

Their high input resistance makes them vulnerable to charge buildup

Why does a reverse-biased PN junction act as a high-resistance element?

The depletion region widens and restricts majority carriers

Why is the common-collector configuration often called an "emitter-follower"?

The emitter output follows the input voltage applied to the base

Which filter is specifically designed to allow only a narrow band of frequencies while rejecting others?

Band-pass filter

Which feature makes the transistor fundamentally different from a diode?

It contains two PN junctions and three terminals

Why have transistors largely replaced vacuum tubes in aviation systems?

They are smaller, more efficient, and more reliable

Which transistor configuration provides phase reversal of the signal?

Common-emitter

Which amplifier class is most efficient but introduces the greatest distortion?

Class C

What distinguishes a notch filter from a general band-stop filter?

It attenuates over an extremely narrow stopband

In an inductor filter, the inductor is effective at:

Blocking AC ripple and passing DC

In a transistor amplifier, why must the emitter-base junction be forward biased while the collector-base junction is reverse biased?

To allow carrier injection at the base and collection at the collector

What role does a capacitor play in rectifier filtering?

Charges and discharges to smooth voltage variations

What determines whether a transistor symbol represents NPN or PNP?

The direction of the arrow on the emitter

Which carrier dominates current conduction in a PNP transistor?

Holes

Which configuration is most commonly used for impedance matching due to its low input resistance and high output resistance?

Common-base

RC coupling is commonly used because:

It blocks DC while passing AC between stages

What is the key difference between positive and negative feedback in amplifiers?

Positive feedback is in-phase with input; negative is out-of-phase

In an NPN transistor, the base is designed to be very thin and lightly doped primarily to:

Reduce electron loss to the base current

Why is Class B more efficient than Class A?

It uses power only for half of the input cycle

The π-type LC filter configuration is named for:

Its schematic resemblance to the Greek letter pi

Field-effect transistors (FETs) differ from bipolar transistors because they are:

Voltage-controlled devices with high input resistance

Which characteristic is essential for operational amplifiers?

Very high gain and high input impedance

The MOSFET channel is considered an "enhancement type" because:

Increasing gate voltage forms and enlarges the conduction channel