The resistance of a circuit is the circuit's opposition to the movement of electrons. A resistor restricts or limits the amount of current flowing in a electrical circuit, it is measured in Ohm (Ω).
Series Resistor: When resistors are connected in series they have one point in common. The total resistance is equal to the sum of the individual resistors.
R tot = R1 + R2 + R3
The current in a series circuit is the same in each component of the circuit because the current must flow through each resistor in series to get to the next resistor. I tot = I1 = I2 = I3
The applied voltage divides across each component in a circuit in proportion to the resistance of the component. V tot = V1 + V2 + V3
Parallel Resistor: When resistors are connected in parallel, they have two points in common. The total resistance of parallel resistors is equal to the reciprocal of the sum of the reciprocal of the individual resistors. R tot of a parallel circuit is called the equivalent resistance, R eq = 1/R 1 + 1/R 2 +1/R 3
