Analog and Digital Electronics Flashcards

Which of the following correctly describes the operation of a MOSFET in the triode (ohmic) region?

Answer: VDS Vth

The triode region requires the channel to be formed (VGS > Vth) and VDS to be small enough that the channel is not pinched off.

The Boolean expression A·(A + B) simplifies to:

Answer: A

By the absorption law, A·(A + B) = A·A + A·B = A + A·B = A(1 + B) = A.

A 3-bit binary counter using T flip-flops requires T flip-flops that toggle on:

Answer: Rising edge for LSB, every 2nd edge for middle bit, every 4th edge for MSB

In a ripple binary counter, the LSB toggles every clock cycle, the next bit every 2 cycles, and the MSB every 4 cycles.

An ideal current source has:

Answer: Infinite internal resistance

An ideal current source maintains constant current regardless of load, which requires infinite internal (parallel) resistance.

In a Phase-Locked Loop (PLL), the voltage-controlled oscillator (VCO) output frequency is controlled by:

Answer: An error voltage derived from the phase detector output

The phase detector produces an error voltage proportional to phase difference, which after filtering drives the VCO to lock onto the reference frequency.

Which hazard in combinational logic circuits produces a momentary incorrect output glitch during input transitions?

Answer: Static hazard

A static hazard causes a brief unwanted pulse (glitch) when a circuit output should remain constant but momentarily changes during input transitions due to unequal path delays.

The gain-bandwidth product (GBW) of an op-amp means that if the open-loop gain is 100,000 and GBW = 1 MHz, the open-loop bandwidth is:

Answer: 10 Hz

Open-loop bandwidth = GBW / open-loop gain = 1×10⁶ / 100,000 = 10 Hz.