Parallel Circuits

Objectives:
1. For the student to investigate the characteristics of a parallel circuit.
2. For the student to verify experimentally, using measured and calculated values, the following parallel circuit rules:
a. The voltage is the same across each branch of a parallel circuit.
b. The sum of the individual branch currents equals the total current in a parallel circuit.
c. The reciprocal of the total resistance equals the sum of the reciprocals of the individual branch resistances.
d. For the student to determine, for a parallel circuit, the effects of changing a single resistor value, upon total
resistance, total current and the distribution of branch currents.
Equipment Required
• Meters: Milliammeter
• Power Supply
• Resistors: 330 W, 1.2 kW, 5.6 kW, 2.2 kW, 33 kW, two 3.3 kW
Information:
1. Always use the measured value of resistance for all calculations.
2. Always adjust the power supply voltage with the circuit connected.
3. When measuring voltage, the voltmeter must be connected across the circuit element of interest.
4. When measuring current, the current meter must be inserted into the “break” in the circuit (in series).