CET CET Analog Electronics and Amplifiers

Question 1

What is the voltage gain of a common-emitter amplifier with a collector resistance of 1 kΩ and emitter resistance of 100 Ω (emitter unbypassed)?

Accepted Answer

10

Answer

Voltage gain equals -Rc/Re; with 1000/100 the magnitude is 10.

Question 2

Which BJT amplifier configuration provides both voltage gain and current gain while inverting the output signal?

Accepted Answer

Common-emitter

Answer

The common-emitter configuration inverts the output and provides both voltage and current gain.

Question 3

What is the primary purpose of a bypass capacitor placed in parallel with the emitter resistor in an amplifier?

Accepted Answer

Increase AC voltage gain by shorting the emitter resistor at signal frequencies

Answer

The bypass capacitor shorts the emitter resistor at AC frequencies, removing negative feedback and increasing gain.

Question 4

In a differential amplifier, what does a high Common-Mode Rejection Ratio (CMRR) indicate?

Accepted Answer

The amplifier effectively rejects signals common to both inputs

Answer

A high CMRR means the amplifier amplifies differential signals while strongly rejecting common-mode (noise) signals present on both inputs.

Question 5

What is the ideal input impedance of an operational amplifier?

Accepted Answer

Infinite

Answer

An ideal op-amp has infinite input impedance so it draws no current from the signal source.

(CET) Certified Electronics Technician Practice Test