Question 1

When a circuit protection device [fuse, circuit breaker] opens due to higher than normal current, a short is the likely cause.

Accepted Answer

When a circuit protection device opens due to higher than normal current, it is likely caused by a short circuit in the circuit.

Question 2

The black DMM test lead always plugs into the COM input jack.

Accepted Answer

The black DMM test lead is always connected to the COM (common) input jack of the meter, while the red test lead is connected to the VΩmA input jack. This is a standard convention followed by most multimeters.

Question 3

High resistance in a circuit causes decreased current flow.

Accepted Answer

Ohm's Law states that current (I) is inversely proportional to resistance (R). Therefore, an increase in resistance causes a decrease in current flow.

Question 4

A switch that is in the closed position should not have more than 300 millivolts voltage drop between input and output terminals.

Accepted Answer

This statement is true. A switch in the closed position should have very low resistance, ideally zero, causing almost no voltage drop between input and output terminals. A maximum of 300 millivolts is an acceptable limit for most applications.

Question 5

If rosin core solder is not available, acid core solder can be used as a substitute.

Accepted Answer

Acid core solder contains flux that is corrosive and can damage electronics, making it unsuitable as a substitute for rosin core solder. It is important to always use the appropriate type of solder for the job to ensure proper conductivity and protection of electronic components.

Question 6

All types of circuit protection devices can be checked with an ohmmeter or test light.

Accepted Answer

Both an ohmmeter and test light can be used to check circuit protection devices, such as fuses and circuit breakers, for continuity or resistance.

Question 7

The schematic for a relay is typically shown on the outside of the relay.

Accepted Answer

The answer of The schematic for a relay is typically...

Question 8

When using a DMM to test resistance, the red lead is connected to the A jack.

Accepted Answer

When using a DMM (Digital Multimeter) to test resistance, the red lead is typically connected to the VΩmA jack (or similarly labeled), not the A jack, which is used for measuring current.

Question 9

Technician A says electrical circuit resistance causes voltage drop. Technician B says high-resistance problems cause an increase in current flow. Who is correct?

Accepted Answer

Technician A is correct. Ohm's law states that electrical resistance causes a drop in voltage. Technician B is incorrect because high-resistance problems decrease current flow, not increase it.

Question 10

A circuit is open when it is complete.

Accepted Answer

A circuit is considered open when there is a break or interruption in the flow of current, which means it is not complete.

Question 11

Connecting an ohmmeter into a live circuit can damage the meter.

Accepted Answer

Connecting an ohmmeter into a live circuit can cause a surge of current to pass through the meter, potentially damaging it. It is important to always de-energize the circuit before measuring resistance.

Question 12

An analog oscilloscope can freeze a captured signal for close analysis.

Accepted Answer

An analog oscilloscope cannot freeze a captured signal for close analysis; it continuously displays a real-time signal. Digital oscilloscopes, however, have the capability to freeze or capture and store signals for later analysis.

Question 13

Connecting an ohmmeter to a live circuit usually results in damage to the meter.

Accepted Answer

Connecting an ohmmeter to a live circuit can cause a surge in current that can damage the meter. The ohmmeter should only be connected to a circuit that is turned off and has no voltage present.

Question 14

An ohmmeter can be used to check for continuity.

Accepted Answer

An ohmmeter can measure the resistance and continuity of a circuit, making it a useful tool for checking if a circuit is complete or if there are breaks or faults in the wiring.

Question 15

Technician A says uses an ohmmeter to measure resistance of a component. Technician B uses a voltmeter to measure voltage drop. Who is correct?

Accepted Answer

Both technicians are correct. Using an ohmmeter is the correct way to measure resistance, while using a voltmeter to measure voltage drop is also correct.

Question 16

While discussing how to test a switch, Technician A says the action of the switch can be monitored by a voltmeter. Technician B says the continuity through the switch can be checked by measuring the resistance across the switch terminals using an ohmmeter. Who is correct?

Accepted Answer

Both technicians are correct. 
Technician A is suggesting using a voltmeter to monitor the action of the switch, meaning that when the switch is turned on or off, the voltmeter will show a change in voltage. 
Technician B is suggesting measuring the continuity of the switch by checking the resistance across the switch terminals using an ohmmeter. This is a way to check if the switch is allowing electrical current to pass through it when closed or not.

Question 17

Technician A says fuses and other circuit protection devices normally wear out. Technician B says to avoid future problems, replace a bad fuse with a higher ampere-rated fuse. Who is correct?

Accepted Answer

Fuses and other circuit protection devices do not normally wear out; they fail when there is a problem in the circuit they protect. Replacing a bad fuse with a higher ampere-rated fuse can cause further damage to the circuit, potentially leading to a fire hazard, so it is not recommended.

Question 18

A wiring diagram shows the actual position of parts on a vehicle.

Accepted Answer

A wiring diagram shows the electrical connections and wiring between parts on a vehicle, but not necessarily their actual physical position.

Question 19

A voltage drop test can find excessive resistance in a circuit that may not be detected using an ohmmeter.

Accepted Answer

An ohmmeter can only detect resistance in a circuit, but it cannot detect if the resistance is causing a voltage drop. A voltage drop test involves measuring the voltage at different points in a circuit and comparing the readings to determine if there is excessive resistance.

Question 20

Analog meters should not be used to test electronic components.

Accepted Answer

Analog meters can cause damage to sensitive electronic components such as transistors and integrated circuits due to their high impedance and voltage spikes. Digital meters are a safer option for testing electronic components.

Quiz 16: General Electrical System Diagnostics and Service