Troubleshooting and Diagnostics Flashcards

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

Answer: The diode has increased forward voltage drop

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

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

Answer: Stuck-at-1 fault

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

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

Answer: Input offset voltage too large or feedback loop open

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

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

Answer: Parallel circuit paths affect the reading

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

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

Answer: The regulator has insufficient input voltage headroom or is failing

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

A technician uses the 'divide-and-conquer' troubleshooting method. This approach involves:

Answer: Testing the midpoint of a signal chain to halve the suspected fault area

Divide-and-conquer splits the signal path at its midpoint, eliminating half the circuit from suspicion with each measurement.

Intermittent faults in electronics are often caused by:

Answer: Cold solder joints or mechanical connection issues

Cold solder joints expand and contract with temperature, creating intermittent electrical contact.