Analog and Digital Electronics Flashcards

In a common-emitter BJT amplifier, increasing the collector resistance RC while keeping other parameters fixed will:

Answer: Increase voltage gain

Voltage gain Av = -gm·RC, so increasing RC directly increases the magnitude of voltage gain.

Which logic gate is equivalent to an AND gate followed by a NOT gate?

Answer: NAND

A NAND gate produces the complement of the AND operation, making it equivalent to AND followed by NOT.

A Schmitt trigger is primarily used to:

Answer: Convert sine waves to square waves with hysteresis

A Schmitt trigger uses hysteresis (two threshold levels) to cleanly convert noisy analog signals into digital square waves.

In a full-wave bridge rectifier with a peak input voltage of 20V and diode forward voltage drop of 0.7V each, the peak output voltage is:

Answer: 18.6V

Two diodes conduct simultaneously in a bridge rectifier, so peak output = 20 - 2(0.7) = 18.6V.

A D flip-flop differs from an SR flip-flop primarily because it:

Answer: Eliminates the forbidden state by tying S and R through an inverter

Connecting an inverter between the S and R inputs ensures S and R are always complements, eliminating the invalid S=R=1 state.

The slew rate of an op-amp limits its ability to:

Answer: Accurately reproduce high-amplitude, high-frequency signals

Slew rate (V/μs) limits the maximum rate of output voltage change, causing distortion when large-amplitude high-frequency signals demand faster output swings.

In a 4-bit ripple carry adder, the worst-case propagation delay occurs when:

Answer: Adding 0111 + 0001

0111 + 0001 forces a carry to ripple through all four stages, producing the maximum carry propagation delay.