Chapter 14 Resistive AC Circuits

2 Objectives –After completing this chapter, the student should be able to: Describe the phase relationship between current and voltage in a resistive circuit. Apply Ohm’s law to AC resistive circuits. Solve for unknown quantities in series AC resistive circuits. Solve for unknown quantities in parallel AC resistive circuits. Solve for power in AC resistive circuits.

3 Basic AC Resistive Circuits –Consist of: An AC source. Conductors. A resistive load.

4 –Source can be: An AC generator. A circuit that generates an AC voltage. –Load can be: A resistor. A heater. A lamp. Any similar device.

5 In phase

6 Effective values –The amount of AC voltage that produces the same degree of heat as a DC voltage of the same value. –Can be considered the DC equivalent value. –Ohm’s law can be used in a pure resistive circuit.

7 Series AC circuits –The current depends on the applied voltage. –The current is always in phase with the voltage. –At any point, the current has the same value.

8 Parallel AC Circuits –The voltage remains constant across each branch. –The total current divides among each branch. –The total current is in phase with the applied voltage. –The individual currents are in phase with the applied voltage.

9 –All current and voltage values are the effective values. –Effective values used the same way DC values are used.

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11 Power in AC circuits –Dissipated in the same way as in DC circuits. –Measured in watts. –Equal to the current times the voltage in the circuit.

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13 In an AC circuit, the average power is the power consumed. –Multiply the effective voltage value by the effective current value: P = IE

14 In Summary –Basic AC resistive circuit A voltage source Conductors A resistive load –In phase –Effective value of AC circuits