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ELCT Class performance (Quizzes 1&2 and Midterm)

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Full wave rectifier circuits

1. In a full wave rectifier circuit, usually a transformer is used to isolate the load from the ac power line, and provide out of phase input voltages.

2. It also allows the designer to choose the input to the rectifier circuit from the turns ratio.

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Diode-bridge full-wave rectifier

Note that the capacitor is half compared to a half-wave rectifier circuit, as the capacitor needs to discharge for only half the time.

The output voltage can be further “smoothed out” by using a regulator circuit.

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Voltage Regulator Circuits

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A Simple Zener-Diode Voltage Regulator

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Calculate the source regulation for a Zener diode with characteristics shown below.

Example on source regulation

In general:

Slope of the load line is -1/R. Thus, change in supply voltage changes the position of the load line, but not the slope

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Load-Line Analysis of Complex Circuits

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Found by considering open circuit in place of the diode in part (b)

Found by considering open circuit in place of the diode and assuming the source to be short circuit

From the Thevenin equivalent circuit, we can write the load equation as:

Example: Analysis of a Zener-diode regulator with load

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Solution continued

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Found by considering open circuit in place of the diode in part (b)

Found by considering open circuit in place of the diode and assuming the source to be short circuit

From the Thevenin equivalent circuit, we can write the load equation as:

Example: Analysis of a Zener-diode regulator with load

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Solution continued

Thus, the solution is : Vd = -10 V, and id = -10 mA