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These 10 free FEAD questions are organized by exam domain, so you can see how each part of the Fundamentals of Electricity - AC/DC (FEAD) blueprint is tested. Reveal the answer and explanation under each question.
A qualified electrician has isolated and locked out all incoming supplies to a control cabinet. The capacitor-discharge waiting period has elapsed, and the power indicator is dark. A verified, correctly rated voltmeter still measures 160 V DC across a power-supply capacitor. Before its terminals can be handled as de-energized, what must be done?
Correct answer: B - Discharge the stored energy by the approved procedure, then verify absence of voltage.
A 120 Ω resistor will remain connected across a regulated 12 V DC supply. The design requires a resistor power rating of at least twice its calculated dissipation. What is the smallest suitable rating among these choices?
Correct answer: D - 3 W
An unloaded voltage divider has a 3.0 kΩ resistor from +24 V to its output and a 6.0 kΩ resistor from the output to 0 V. A device with a purely resistive 3.0 kΩ input is connected between the output and 0 V. Neglect component tolerances. What voltage will the device receive?
Correct answer: D - 9.6 V
On an isolated, de-energized control board with discharged capacitors, a resistor marked 2.2 kΩ ±5% measures 1.5 kΩ while still soldered in place. The meter reads a separate reference resistor correctly. Which step will establish whether the resistor itself is out of tolerance?
Correct answer: A - Disconnect one resistor lead and measure directly across the resistor.
The AC-voltage display on a multimeter reads 24.0 V RMS across a purely resistive heater supplied by a sine wave. In physical terms, what does this reading represent?
Correct answer: A - The DC voltage that would deliver the same average heating power to that resistor.
During an AC test, an ideal capacitor is connected to a sinusoidal source whose RMS voltage stays constant. The frequency is increased. How do the capacitor's RMS current and its phase relationship to the voltage respond?
Correct answer: D - Current increases and continues to lead voltage by 90°.
A permanent-magnet DC motor drives a conveyor from a fixed-voltage supply. When mechanical load increases within the motor's rating, its speed settles slightly lower and armature current rises. Which explanation accounts for both observations?
Correct answer: C - Slower rotation reduces back emf, leaving more of the supply voltage to drive armature current.
Why does an AC power network use a step-up transformer before a long transmission line and a step-down transformer near the loads? Compare delivery of the same real power at the same power factor through conductors of unchanged resistance.
Correct answer: D - The higher transmission voltage allows less current, reducing resistive line losses.
A control transformer rated 230 V primary, 24 V secondary, 60 Hz has a single primary winding with no taps. It is mistakenly supplied with 115 V at 60 Hz. Its secondary feeds a relay that requires at least 18 V RMS to pull in. Treating the transformer as ideal, identify the expected secondary voltage and relay response.
Correct answer: B - 12 V RMS; the relay will not pull in.
The relay in a 24 V DC indicator circuit pulls in, but the lamp stays dark. The load path is supply positive, normally open relay contact, lamp, then supply negative. With the relay held energized, measurements show 24 V across the supply, 24 V across the contact, and 0 V across the lamp. Assuming one open-circuit fault, where is the interruption?
Correct answer: C - Within the relay's switched contact path.
The FEAD exam also covers these domains. Drill them in the full free practice test:
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