All Tutorials / Steve G / Amps, Volts, Power Converters and Power Supplies.

Amps, Volts, Power Converters and Power Supplies.

Step 9. Wire and cable.

Love it or hate it, wire and cables are an important aspect for any electrical system. Most electrical devices will use wire at some point in their makeup. Whether it's a mass of wire connecting different components together, a couple of wires connecting battery terminals to a circuit board, or a completely wire free device that needs to be recharged that will use a mains power charger.

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When building an electrical system, you will need to work out the power requirements for devices or peripherals used, such as the servos or DC motors that have been previously mentioned. Using an inadequate wire gauge connected to a DC motor for example, can cause the motor to not operate properly, and the wire can heat up excessively.

The difference between wire and cable is a simple one to remember.

A single or multiple metal wire strands that conduct electricity (normally copper or aluminum), make a wire.

A cable, is made up of multiple wires.

Take a three core cable for example. This is made up of three wires (cores) which are usually "Earth or Ground", "Live or Positive", and "Neutral or Negative" wires.

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Wire comes in different thicknesses which is referred to as "Gauge". This is measured in millimeters and gauged in "SWG" (British Standatd wire gauge, and "AWG" American wire gauge). Understanding this is important. When it comes to the actual wire sizes, AWG and SWG are not equivalent in size. In general, an SWG wire would be bigger than an AWG wire of the same gauge. AWG is more widely used nowadays, although SWG measurements are used in some industries. So when working out your wire gauges, it's worth taking this in to consideration. Gauge measurements work out as a thin wire will be a high gauge number, and a thick wire will have a low gauge number. Much like the "waterwheel" analogy used to explain the flow of amps, the larger water pipe can deliver more current/amps, and the same is usually true for thicker wire.

Below is a wire gauge table that gives the maximum amp rating for different wire gauges...

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Pushing or drawing a higher amp rate than the wire is rated for, will cause the wire to heat up and possible melt the plastic, rubber, or silicone covering. This can cause short circuits and possibly burst in to flames.

The quality of wire varies as well, so make sure you get a good quality wire.