1. 4.2.5 Parallel Circuits Wiring for Voltage

2. Definitions parallel circuit – a circuit in which two or more elements are connected so that each has its own current loop.

3. Parallel Circuit Rules equivalent Resistance – more resistors = less resistance 1/R eq = 1/R 1 + 1/R 2 + … current – currents add up I = I 1 + I 2 + … voltage – voltages same for each resistor V = V 1 = V 2 = … All circuit components and the circuit as a whole must obey Ohm’s Law

4. Junction Rule The total current flowing into and out of a junction must be the same 10 A 4.0 A ?6.0 A

5. Junction Rule ? 2.0 A 10 A ? 6.0 A 4.0 A6.0 A

6. V (V)I (A)R (Ω) R1R1 R2R2 R3R3 R eq 10 30 6.0 2.0 60 R 1 = 30 Ω R 2 = 30 Ω R 3 = 30 Ω 60 V

7. V (V)I (A)R (Ω) R1R1 R2R2 R3R3 R eq 5.9 20 50 10 0.85 0.25 0.1 0.5 5.0 R 1 = 20 Ω R 2 = 50 Ω R 3 = 10 Ω 0.5 A

8. End of 4.2.5 – PRACTICE