Electrical/Electronic Systems Flashcards

A duty cycle of 75% on a PWM-controlled circuit means the signal is:

Answer: On for 75% of each cycle

Duty cycle expresses the percentage of each cycle that the output is energized.

Which tool safely back-probes a connector without piercing the wire insulation?

Answer: A back-probe pin or T-pin at the connector rear

Back-probing from the rear of the connector contacts the terminal without damaging insulation or wire strands.

An electromagnetic field collapsing in an ignition coil's secondary winding produces:

Answer: High-voltage output to fire the spark plug

When the primary field collapses, mutual induction in the many secondary windings produces tens of thousands of volts.

A vehicle's wiper motor runs slowly and draws excessive current. The most likely cause is:

Answer: High mechanical resistance or worn motor brushes/bushings

Mechanical binding or worn brushes increase motor load, slowing it and raising current draw.

What does a waveform's flat-line at zero volts on a lab scope typically indicate for a signal that should be active?

Answer: A loss of signal, open, or no power to the device

A dead flat line at zero where activity is expected usually means the circuit is open or unpowered.

In a series circuit, if one bulb burns out (opens), the other bulbs will:

Answer: Go out because the circuit is broken

Series circuits share a single path, so an open in one component stops all current flow.

A technician should set a DMM to which function to verify continuity of a fusible link?

Answer: Ohms or the continuity/beep setting

Continuity or low-ohms mode confirms whether the fusible link provides an unbroken path.