Write the formulas that express the relationships between voltage, current, and resistance in a circuit.
E = I × R, I = E ÷ R, R = E ÷ I
Why are many automotive circuits frame-ground circuits?
Using the vehicle frame for ground saves wiring because a return wire does not have to be used to carry current back to the power source.
If voltage rises what a happens to current?
Nothing
Current goes down
Current goes up
True or false? Most automotive electrical problems are caused by a change in circuit resistance.
True
Calculate the total resistance and current for the following circuit.
Rt = 10 + 3 + 7 + 2 = 22Ohms, It = 12.6V 22Ω = 0.57A
In a one-wire circuit, the vehicle's _____ serves as a large conductor to carry current.
frame
Why does the automotive industry use one-wire or frame ground circuits?
to limit the amount of wires need to complete the circuit
I represents _______________________.
Watts
Ohms
Current
Voltage
Technician A says a series circuit has only one path for current. Technician B says a series circuit can have only one load. Who is right?
A only.
Neither
B only
Both
True or False? Most automotive electrical problems are casued by a change in circuit resistance.
True
True or False? An ammeter is a device that measures resistance of a circuit.
False
When a switch is ________________________, current cannot flow through it.
open
Technician A says current is the same everywhere in a series circuit. Technician B says current is the same in each branch of a parallel circuit. Who is right?
B only
Neither
Both
A only
In what way is a parallel circuit different from a series circuit?
A parallel circuit has more than one path for current flow. A series circuit has only one path for current flow.
What does DVOM stand for?
Digital Volt Ohm Meter
In which type of circuit can you find total resistance by adding all of the individual resistances?
Series
A 12-volt circuit has a resistance of 2 ohms. How much current is in the circuit?
8 amps
5 amps
4 amps
6 amps
R represents ______________________.
Watts
Current
Ohms
Voltage
If voltage drops what happens to current?
Nothing
Current goes down
Current goes up
E represents ______________________.
Current
Ohms
Voltage
Watts
Technician A says a change in circuit resistance will change the amount of current in the circuit. Technician B says a change in circuit voltage will change the amount of current in the circuit. Who is right?
Both
A only
Neither
B only
If resistance increases in a circuit, what will happen to current?
Current will decrease.
If resistance rises what happens to current?
Current goes down
Current goes up
Nothing
What is a series-parallel circuit?
A series-parallel circuit is a circuit in which some components are wired in series, but others are wired in parallel.
If resistance drops what happens to current?
Current goes up
Nothing
Current goes down
The ____________________________ is the unit of measurement for electric power.
Watt
Which of the following is not a common type of electric circuit?
Parallel Circuit
Series-ground circuit.
Series- Parallel Circuit
Series Circuit
If a circuit has a current of 3 A and a resistance of 5 Ω, how much voltage is applied to the circuit?
15 V