Resistor, Relay, Transformer??

[JamesKenton]

Hi

Can anyone with anyone eletcircal knowledge kindly explain to me what these elctrical components/parts do, or are for:

Resistor,
Relay
Transformer

Thanks for your help

 

[Steve]

Resistor - pretty simple - resists the flow of electrons using semiconductor material.

Relay - a little more involved - uses a "light" circuit to control a "heavy circuit". For example, in a car. The headlights draw about 9 amps (plus the tail lights). This is too much for the little switch on the stalk to handle. So the stalk switch is wired in small wiring, which turns on a relay. The relay is a solenoid (coil of wire with an iron core which moves when coil is energised). The solenoid mecahnically activates one of more contacts. A contactor is a relay, but they are used on heavier loads and industrial applications - they have more robust operation.

Transformer - hmmm. Two coils of wire wrapped around an iron core. An input and an output. By varying the numbers of turns on the two coils, you can change the output voltage in direct proportion (for example, input at 230V AC = 230 turns on the input. If you want an output at 110V AC, you turn the secondary coil 110 times).

Of course, theres a little more to it than this. All the answers are available online! Try google.