CET Troubleshooting and Diagnostics 3

Question 1

A half-wave rectifier produces a lower-than-expected DC output. Which component failure is most likely?

Accepted Answer

The diode has increased forward voltage drop

Answer

An increased diode forward voltage drop reduces the peak output voltage of the rectifier.

Question 2

When troubleshooting a logic circuit, a gate output is stuck HIGH regardless of inputs. This is called a:

Accepted Answer

Stuck-at-1 fault

Answer

A stuck-at-1 fault means the node is permanently logic HIGH regardless of normal switching inputs.

Question 3

An op-amp circuit has its output rail-to-rail with no input signal applied. The most likely cause is:

Accepted Answer

Input offset voltage too large or feedback loop open

Answer

A large input offset or open feedback loop causes the high open-loop gain to drive the output to saturation.

Question 4

During in-circuit testing, measuring resistance on a powered circuit gives unreliable results because:

Accepted Answer

Parallel circuit paths affect the reading

Answer

Parallel paths in a circuit provide alternative current routes, making in-circuit resistance readings inaccurate.

Question 5

A voltage regulator IC output drops when load current increases. This symptom suggests:

Accepted Answer

The regulator has insufficient input voltage headroom or is failing

Answer

A linear regulator needs a minimum input-output differential (dropout voltage); insufficient headroom or a failing IC causes output sag under load.

(CET) Certified Electronics Technician Practice Test