Skip to main content

Precision rectifier circuit

Short answer

A precision half‑wave rectifier places diodes inside an op‑amp’s feedback loop to eliminate diode drop. In the inverting version, for negative inputs Vo = –(Rf/R) Vin, for positive inputs Vo = 0; a non‑inverting version gives Vo = Vin for Vin>0.

Draw the circuit diagram of precision rectifier circuit.

A precision (super-diode) half-wave rectifier uses an op-amp with the diodes inside its feedback loop, so that it rectifies voltages smaller than the diode drop.

Circuit diagram (inverting half-wave type)

                +---------[ Rf ]----------+
                |                         |
                |     D1                  |
                +-----|>|------+          |
                |              |          |
 Vin o---[ R ]--+--(-)\        |    D2    |
                       >-------+---|>|----+-----o Vo
           GND ----(+)/                   |
                                        [RL]
                                          |
                                         GND
  • D1 (anode at the inverting node, cathode at the op-amp output) conducts for positive Vin. It keeps the loop closed, and the output is Vo = 0.
  • D2 (anode at the op-amp output, cathode at Vo) conducts for negative Vin, and Vo = −(Rf/R) Vin, which is a positive half-wave.

Non-inverting alternative: a single diode in series with the output of a voltage follower, with the feedback taken from the cathode side of the diode and a load resistor to ground: Vo = Vin for Vin > 0 and 0 otherwise.

✓ Answer checked by Claude Opus 5.5 (high effort)

Related questions

All Electronics Devices and Circuit chapter 5 questions →