1. Parallel Circuits – Chapter 5
A parallel circuit provides more than one current path between any two points.
Each current path in a parallel circuit is referred to as a branch.
Two Branches Three Branches
How many branches?

2. Parallel Circuit Characteristics
Voltage and Current Values
Voltage is the same across all components
(a) No parallel branches (b) V1 = V2 = VS

3. Parallel Circuit Characteristics
Current Characteristics
Source current is the sum of all branch currents
where
In = the current through the nth branch in the circuit

4. The total current in the circuit is IT = I1 + I2 + I3
IT = 5mA + 10mA + 20mA = 35mA

5. Parallel Circuit Characteristics
Voltage and Current Values
Current through each branch is determined by the source voltage and the resistance of the branch.

6. TEAM ACTIVITY
Use Ohm’s law to calculate the resistance in each branch.

7. TEAM ACTIVITY

8. TEAM ACTIVITY
Use Ohm’s law to calculate the total resistance.

9. TEAM ACTIVITY

10. TEAM ACTIVITY
Calculate

11. Summary

12. Common Mistake

13. TEAM ACTIVITY

14. TEAM ACTIVITY

15. Special Case – Equal Resistances
When any number of equal resistances are connected in parallel, the total resistance is equal to the value of one resistor divided by the number of branches
Shorthand notation for parallel

16. Special Case – Equal Resistances
Shorthand notation for parallel

17. Adding Additional Branches
The addition of a parallel branch decreases the resistance of the circuit
single branch in (a) draws 5mA from the source
additional branch in (b) increases the current drawn from the source to 10mA

18. TEAM ACTIVITY
Determine the branch currents and the total current for each circuit. Check with MultiSim.