10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
These 10 free EIMC questions are organized by exam domain, so you can see how each part of the Electricity Introduction, Measurement, and Circuits Certification blueprint is tested. Reveal the answer and explanation under each question.
A battery-powered lamp is dim during an approved loaded test. The battery measures 12.0 V at its terminals, a connector in the positive lead drops 4.0 V, and the lamp receives 8.0 V. The switch and return lead have negligible drops. The connector's permitted drop at this load is 0.10 V. Where should the next de-energized inspection focus?
Correct answer: A - The connector, for unwanted resistance at its contacts.
Two batteries have the same nonzero open-circuit voltage. Each is modeled as an ideal voltage source in series with a constant internal resistance. Connected separately to the same fixed load resistor, battery B produces a lower terminal voltage than battery A. Compared with A, battery B has:
Correct answer: A - Higher internal resistance and lower load current.
After measuring current, a technician switches off a DC trainer and disconnects both probes. The black lead remains in COM; the red lead remains in A. Before measuring the source voltage with power restored, configure the meter as follows:
Correct answer: C - Move red to V/Ω, select DC V, and connect across the source.
A service note for an isolated resistor reads: 'Accepted range: 450-490 Ω. Measured resistance: 468 Ω. No continuity tone, so replace.' The meter sounds a tone only at 30 Ω or less. What correction does this note need?
Correct answer: B - Remove the replacement decision; both results are expected.
The measurements for one load in a DC trainer are: source voltage, 24.0 V; voltage across the load, 9.0 V; current through the load, 30.0 mA. Meter loading is negligible. Enter the calculated resistance of that load on the service sheet.
Correct answer: B - 300 Ω
R1 and R2 were operating in series from a constant 12 V DC supply. A single fault raises the source current. R2 now has zero voltage across it, while R1 has the full 12 V. The supply voltage and all other wiring remain unchanged. Diagnose the fault.
Correct answer: D - A short circuit across R2.
With the source physically disconnected, an ohmmeter across R1 reads below R1's marked resistance. R2 is still connected across the same two nodes; these are the network's only components. Before rejecting R1, how can its resistance alone be checked?
Correct answer: D - Disconnect one end of R1, then measure directly across R1.
A test load must present 120 Ω between its two terminals. An existing 300 Ω resistor will remain connected across those terminals. Choose the additional resistor to connect across the same terminals to obtain the required equivalent resistance.
Correct answer: B - 200 Ω
A wiring diagram identifies three connections: R1 joins supply positive P to junction X; R2 joins X to supply return N; R3 joins P directly to N. Nothing else connects to X. The components are rearranged on the drawing without changing the wiring. Select the topology that still describes the circuit.
Correct answer: C - R1 and R2 in series, with that branch in parallel with R3.
A 12 V divider uses two 1 MΩ resistors in series. Meter X has 1 MΩ input resistance; meter Y has 10 MΩ. Both read correctly at the source, but X reads lower than Y across the lower resistor when used separately. There is no other output load. Which choice gives an output-voltage reading with the least loading error?
Correct answer: D - Use meter Y across the lower resistor.
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