ISCET Component-Level Troubleshooting 2

Question 1

A technician measures voltage across a diode in forward bias and reads 0 V. What is the most likely fault?

Accepted Answer

Diode is shorted

Answer

A shorted diode drops 0 V because it conducts without resistance, unlike a normal forward-biased diode which drops ~0.6–0.7 V.

Question 2

When testing a capacitor with an ohmmeter, the needle deflects then slowly returns to infinity. This indicates the capacitor is:

Accepted Answer

Functional

Answer

A good capacitor charges from the ohmmeter's battery, causing a momentary deflection, then returns to infinite resistance as the charge stabilizes.

Question 3

Which instrument is best suited for checking the switching speed of a transistor in a digital circuit?

Accepted Answer

Oscilloscope

Answer

An oscilloscope displays waveform timing and transition characteristics, making it ideal for measuring transistor switching speed.

Question 4

A NPN transistor has VBE = 0 V and VCE = VCC. The transistor is most likely:

Accepted Answer

In cutoff

Answer

With VBE = 0 V, no base current flows, placing the transistor in cutoff, so VCE equals the full supply voltage.

Question 5

A resistor measures 10% above its marked value. The technician should:

Accepted Answer

Accept it if within its tolerance rating

Answer

If the measured deviation falls within the resistor's specified tolerance (e.g., ±10% or ±20%), the component is acceptable.

(ISCET) International Society of Certified Electronics Technicians Practice Test