Automotive Circuits

Automotive Circuits:
Source----protection----control----consumer.

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Series circuit
There is only one voltage supply to the circuit voltage must pass to each consumer therefore it's shared by all consumers, not necessary equally, but depending on the varying resistances of the circuit.
The current is the same in all areas of the circuit.

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Parallel Circuit:

A parallel circuit has more than one input and output, depending on the number of electrical consumers.

Each consumer therefore has its own input and output.

Current draw for this circuit is high!

(The total Resistance of a parallel circuit is Always smaller than the smallest Resistor)

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Compound:

Series/Parallel Circuit or Compound Circuit:
This circuit is made up of part series and part parallel combinations.
When doing calculations in compound circuits, always work out the total resistance of the parallel area first.

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Potential difference (Symbol=E), measured in volts.

The difference between the high potential positive terminal and the low potential negative terminal when using a volt meter.

Electromotive force is another term for(E) but refers to the voltage between the termianls of the alternator or the battery with no load applied.

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Hertz (Symbol=Hz) is the unit of frequency this is defined as the number of cycles per second.

Farad: A farad is the unit of capacitance defined by the radio of charge stored on the plates of a capacitor to the potential difference between the plates. Example: if 56mA current cause the voltage across a capacitance of 56mF.

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Electrical  Calculations.

This formula is used to find total resistance of a parallel circuit at level four.

 1/Rt=1/R1+1/R2+1/R3

Calculate the total resistance using the formula for parallel circuit and the current flow through the circuit.

Electrical Terms

Voltage:
Practical unit of pressure;
practical unit of electromotive force.
The force or pressure that is required to move the electrons in a circuit.

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Ohms:
This is the unit of resistance.
The resistance to the flow of electrons.
Resistance is introduced into a circuit to reduce or limit current flow and voltage.
It's important to have an understanding of resistance for calculation purposes.

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Ampere=Unit of current.
When electrons move along a conductor,this means there is now current flowing in the circuit measured in amperes(amps).The more electrons flowing,the larger the current.

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Wattage:
Practical unit of power.(work being done)
In an electrical circuit, if you multiply the voltage maintained across the circuit, by the amperes flowing through the circuit, this will equal to the power output, or dissipation in Watts.

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P=V*I(amps)

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Conventional current flow:
Conventional current flow from positive to Negative.

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Electron flow:
Electrons flow in the opposite direction to conventional.

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Current flow:
Current flow from Negative to Positive.