Resistor and Resistance

A resistor resists the flow of electricity.

Resistance is measured in ohms which is an international unit

Resistance was discovered by Georg Simon Ohm.

Lower resistance allows more current to flow.

A higher voltage overcome resistance and increase the current.

Interesting fact

When a human tongue is moist with saliva then it has a resistance of 50k and hence we get a tingling sensation when we touch a battery to it

Insulator is a material that has a very high resistance to electricity

Conductor is a material that has a very low resistance to electricity.

Example : Copper, Aluminum, Silver and Gold are excellent conductors

Potentiometers are variable resistors which allows you to vary the voltage and current by varying the resistance.

It consists of a circular track of conductive plastic or a loop of coiled wire which posesses some resistance and as you turn the shaft of the potentiometer,a wiper rubs against the resistance.

Interesting fact

The potential difference(The voltage drop) between the cathode and the anode of a tiny old fashioned bulb varys much more than a LED as the light bulb acts as a pure resistor while an LED self adjusts to some extent, modifying it's resistance as the voltage pressure changes.