CET Troubleshooting and Diagnostics 2

Question 1

A technician measures voltage across a resistor and gets 0V, but the source voltage is present. What is the most likely fault?

Accepted Answer

The resistor is shorted

Answer

A shorted resistor allows all voltage to drop elsewhere, leaving 0V across it.

Question 2

When using an oscilloscope to troubleshoot, a waveform appears 'clipped' at the top. This most likely indicates:

Accepted Answer

Amplifier saturation or clipping

Answer

Flat tops on a waveform indicate the amplifier is driven into saturation, clipping the output.

Question 3

A capacitor in a filter circuit is suspected faulty. Which test best confirms an electrolytic capacitor has dried out?

Accepted Answer

ESR (Equivalent Series Resistance) measurement

Answer

ESR measurement directly reveals increased internal resistance caused by electrolyte drying.

Question 4

In a transistor circuit, collector-to-emitter voltage equals the supply voltage. This indicates:

Accepted Answer

The transistor is cut off (open)

Answer

When VCE equals supply voltage, no current flows through the collector, meaning the transistor is cut off.

Question 5

A technician finds a circuit board with a burned resistor. After replacing it, the resistor burns again. What should be done next?

Accepted Answer

Check the circuit for the root cause of excessive current

Answer

A recurring burned resistor indicates an underlying fault causing overcurrent that must be identified and corrected.

(CET) Certified Electronics Technician Practice Test