AFCT Electronics: Components and Functions 3

Question 1

What is the function of a relay in an electronic circuit?

Accepted Answer

To use a small current to control a larger current by electromagnetic switching

Answer

To amplify weak signals

Answer

To convert DC to AC

Answer

To regulate voltage output

Question 2

What does an LED (Light Emitting Diode) require in a circuit to operate safely?

Accepted Answer

A current-limiting resistor in series

Answer

A transformer to step up voltage

Answer

A capacitor in parallel for energy storage

Answer

An inductor for impedance matching

Question 3

What is the difference between an NPN and a PNP bipolar junction transistor?

Accepted Answer

NPN conducts when the base is more positive than the emitter; PNP conducts when the base is more negative than the emitter

Answer

NPN uses electrons and PNP uses protons as charge carriers

Answer

NPN is used for amplification and PNP is used only for switching

Answer

There is no functional difference between them

Question 4

What is the primary purpose of a transformer?

Accepted Answer

To transfer electrical energy between circuits through electromagnetic induction, changing voltage levels

Answer

To convert DC voltage to AC voltage

Answer

To store large amounts of electrical energy

Answer

To amplify current in a circuit

Question 5

What is the function of an operational amplifier (op-amp) in a circuit?

Accepted Answer

To amplify the voltage difference between its two inputs with very high gain

Answer

To convert AC to DC power

Answer

To store charge like a capacitor

Answer

To generate oscillating signals without external components

Question 6

What component protects sensitive electronics from voltage spikes?

Accepted Answer

Metal Oxide Varistor (MOV)

Answer

Thermistor

Answer

Potentiometer

Answer

Crystal oscillator