Circuit basics: Resistance

Last time we discussed the resistor. I promised to do a post on resistance as the resistor is quite useless if you don't know about resistance. So what is resistance?

If you imagine electrical current as a water flow, you can imagine the resistor as narrowing of the pipe as can been seen in the following image. We already learned that voltage can be seen as water pressure. At point A the water pressure could be, for example, 8 Volts. Because of the resistor, the water can not flow freely to point B. The pressure at point B would be lower, let's say 6 Volt. This means that the resistor resists 2 Volts.

Basically that's it. It's not very hard to understand resistance, but using it in your circuit is much harder. Next time we investigate resistance using resistors in a circuit.