To what do the "rails" of an operational amplifier refer?

Which of the following statements about phase-locked loops is NOT true?

What standard logic operation is represented by a household "three-way switch" in which two different switches operate the same light fixture?

What is the function of a diode clamp?

Which of these statements expresses De Morgan's theorem?

What artifact results from a failure to low-pass filter a signal before analog-to-digital conversion?

In a low-pass filter consisting of a resistor and a capacitor, how will the cut-off frequency change if the capacitance is increased?

What is the name for the configuration in which an operational amplifier (op-amp) has its output connected to the non-inverting input?

A high-voltage primary circuit is isolated with the use of an optocoupler on a secondary circuit. Does the addition of the optocoupler add inductance to either circuit?

What is the term to describe a multivibrator circuit with two outputs, both of which are stable in time?

A JK flip-flop circuit can be assembled entirely from four of which type of digital gate?