introduce to Resistor

Resistors determine the flow of current in an electrical circuit. Where there is high resistance in a circuit the flow of current is small, where the resistance is low the flow of current is large. Resistance, voltage and current are connected in an electrical circuit by Ohm’s Law.

RESISTORS IN SERIES AND IN PARALLEL
Resistors can be connected together in two ways to give different overall values. This is especially useful if you do not have a resistor of the correct value and need to make it up from other available ones.
1. Resistors in SERIES - When resistors are connected in series, their values are added together:
For example: 1K+1K+3K9=5K9 (total value)
2. Resistors in PARALLEL -When resistors are connected in parallel, their total resistance is given as:
For example: 1/Rtotal = 1/1K + 1/1K = 0.5K or 500 ohms