In the center tap full wave rectifier, current flows through the load in the same direction for both half cycles of input AC voltage. The circuit shown in Figure has two diodes D1 and D2 and a center tapped transformer. The diode D1 is forward bias “ON” and diode D2 is reverse bias “OFF” in the positive half cycle of input voltage and current flows from point a to point b. Whereas in the negative half cycle the diode D1 is reverse bias “OFF” and diode D2 is forward bias “ON” and again current flows from point a to point b. Hence DC output is obtained across the load.
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| Figure: Center-tap diode rectifier |
ADVANTAGES OF CENTER TAP DIODE RECTIFIER
• The need for center-tapped transformer is eliminated,• The output is twice that of the center tapped circuit for the same secondary voltage, and,
• The peak inverse voltage is one half of the center-tap circuit.
DISADVANTAGES OF CENTER TAP DIODE RECTIFIER
• It requires four diodes instead of two, in full wave circuit, and,• There are always two diodes in series are conducting. Therefore, total voltage drop in the internal resistance of the diodes and losses are increased.