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Basic theory
All electrical circuits rely on some form of connection.
Current is the rate of flow of electrical charge .The flow of current through any metallic conductor is proportional
to the voltage applied across it.
Resistance (R) to current flow is dissipated as heat.
Power is the energy availabe per unit time to do work.
Energy is measured in joules (J).
Power is measured in Watts (W) and is one joule per second (1J/s)
Power(W)=Current(I) x Volts (V)
The importance of a good connection
Poor electrical connections caused by high resistance result in loss of power available due to some of the energy converting
to heat.
Heat produced can cause a fire to occur.
A typical example would be a poor connection in a starter motor power circuit. The motor may require for example, 1 kilowatt
(1000W) of electrical power to turn the engine over fast enough to enable starting (usually around 200rpm at the crankshaft)
and will need to draw current (P=IxV)of around 83 amps (possibly a bit more due to friction etc).
A bad circuit joint with high resistance will cause a voltage drop meaning less power available so the starter turns the
engine over more slowly.
Voltage level is used as a signal in some electrical circuits. If high resistance occurs the voltage drops and may not
allow the circuit to work properly.
Soldering
Soldering is a preferred method used to join wires by using a molten mixture of lead and tin using a soldering iron.
Soldered joints may be insulated using products such as heat shrink tubing. A small blow torch similar to the one shown below
can be used to provide heat to shrink the tube in non flammable environments.
Crimped Connectors
Many types of crimped connectors exist . Plug and socket designs allow quicker disconnection if required for testing etc.
A special crimping tool is required for each type of connector. Using the incorrect crimping tool can result in unreliable
joints.
Mechanical Connectors
Many connectors have a mechanical device such as a bolt or screw which tightens onto the wire to secure it.
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