Series and parallel circuits
- 1. Series and Parallel Circuits
- 2. Series Circuit • Series circuit - has only one path through which the electricity can flow. • In the above diagram, the electricity flows through both loads.
- 3. Current and Resistance in Series Circuits • For the series circuit the same current flows through both loads. • The loads can be added together to calculate the total load. • Rtot = R1 + R2, where Rtot is the total resistance, R1 is the resistance of one load, and R2 is the resistance of the other. • The total load (resistance) in a series circuit with “n” loads is the sum of the resistance of the “n” objects. Rtot = R1 + R2 + … + Rn.
- 4. Total Voltage in a Series Circuit • Ohm’s Law can be used to calculate the total voltage in a series circuit by calculating the sum of the voltage parts. • V = V1 + V2, where V is the total voltage (battery voltage), V1 is the voltage at the first load, and V2 is the voltage at the other load.
- 5. Parallel Circuits • A parallel circuit has multiple paths through which the electricity can flow. • In a parallel circuit, the current though one path may be different than the current through the other path.
- 6. Current in a Parallel Circuit • The total current in a parallel circuit is the sum of the two parts. • I = I1 + I2, where I is the total current, I1 is the current through one load, and I2 is the current through the other load. I1 I2
- 7. Resistance in Parallel Circuits • Using Ohm’s Law you can derive a formula for the equivalent resistance of two resistors in parallel. • I1 = V/R1 • I2 = V/R2 • I = I1 + I2 = V/R1 + V/R2 • = (VR2 + VR1)/R1R2 = V(R2+R1)/R1R2 • Rtot = V/(V(R2+R1)/ R1R2 = R1R2/ (R1+R2)