Analog and Digital Electronics Flashcards

In an R-2R ladder DAC, the primary advantage over a binary-weighted DAC is:

Answer: Only two resistor values are needed regardless of bit count

The R-2R ladder uses only two resistor values (R and 2R) for any number of bits, making precision matching much easier to manufacture.

Which configuration of an op-amp provides the highest input impedance?

Answer: Voltage follower (unity gain buffer)

A voltage follower connects the output directly to the inverting input with the signal at the non-inverting input, yielding input impedance approaching infinity due to near-zero differential input voltage.

In a JK flip-flop, setting J=1 and K=1 causes the output to:

Answer: Toggle to the complement of Q

The J=K=1 condition is the toggle mode of the JK flip-flop, where Q changes to its complement on each active clock edge.

A Wien bridge oscillator uses which type of feedback network to set oscillation frequency?

Answer: RC lead-lag network

The Wien bridge uses an RC lead-lag network that provides 0° phase shift at the resonant frequency f = 1/(2πRC), setting the oscillation frequency.

In digital logic, the fan-out of a gate refers to:

Answer: The maximum number of identical gate inputs a gate output can reliably drive

Fan-out specifies how many standard gate inputs can be connected to a single gate output while maintaining valid logic levels.

The Early effect in a BJT manifests as:

Answer: Non-zero output conductance causing IC to increase slightly with VCE

The Early effect (base-width modulation) causes the effective base width to shrink with increasing VCE, slightly increasing collector current and creating finite output resistance.

A 4-to-16 decoder can be constructed from:

Answer: Two 3-to-8 decoders with an enable input

Two 3-to-8 decoders with enable lines can be combined — one upper address bit selects which 3-to-8 decoder is active, giving 16 total outputs.