precision full wave rectifier

EXPT.1 - PRECISION RECTIFIER

AIM: Design and test the working of Full Wave Precision Rectifier using op-amp

THEORY: Precision Rectifier name itself suggests that it rectifies even lower input voltages i.e. voltages less than 0.7v (diode drop). A rectifier is a device, which converts AC voltage to DC voltage. Precision rectifier converts AC to pulsating DC. Normal rectifiers using transformers cannot rectify voltages below 0.7v, so we go for precision rectifiers. In this circuit the diodes are placed in such a way that one diode is forward biased in the positive half cycle and the other in the negative half cycle. Consider the circuit diagram shown below. Here in the positive half cycle D1 is forward biased and D2 is reverse biased. The simplified circuit will act as two inverted amplifiers connected in series. Hence the total gain will be the product of individual gains. During the negative half cycle, D1 is reverse biased and D2 is forward biased. Hence the simplified circuit is an inverting amplifier connected in series with a non-inverting amplifiers. Hence the output will be inverted and a DC output (unidirectional) is obtained .The precision rectifier we are using is a full wave rectifier.

PROCEDURE:

1. Rig up the circuit as shown in the circuit diagram.

2. Give an input of 2V peak to peak (sine wave).

3. Check and verify the designed values.

4. Design the same circuit for a different set of values.

RESULT: