Voltage Drop Testing Flashcards
What is voltage drop?
The amount of voltage dropped or consumed as it passes through a load or any resistance in a circuit.
What should most of the battery’s voltage (12.6V) be consumed by?
The load.
What components in a circuit typically have some resistance?
Wires, switch contacts, and connection points.
What does performing a voltage drop test determine?
The cause of excessive, abnormal resistance.
What is the purpose of voltage drop testing?
To determine if too much voltage is being lost to poor connections.
What scale should the voltmeter be set to during voltage drop testing?
Low voltage, DC scale (0-2V or the mV scale).
What must be true about the circuit during voltage drop testing?
The circuit must be turned on and there must be current flowing.
Where should the meter leads be placed when testing voltage drop?
Across the connection being tested (in parallel).
What should not exceed a loss of voltage per connection during testing?
0.1V loss per connection.
What is the maximum total voltage drop on the V+ or ground side of a circuit?
0.3V – 0.5V (300mV – 500mV).
What does a lower reading in voltage drop testing indicate?
The better the connection.
Which sides of a circuit can be tested for voltage drop?
Both the positive and ground side.
Fill in the blank: The bulk of the battery’s 12.6V should be _______ by the load.
[used up]
True or False: A voltage drop test can be performed only on the positive side of a circuit.
False.
What does a voltage drop test on the V+ side of the alternator output circuit measure?
The voltage drop across the output terminal.
What does a voltage drop test on the ground side of the alternator circuit measure?
The voltage drop across the alternator case ground.
