Precision full-wave rectifier circuit (4 diodes type)

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Precision full-wave rectifier circuit (4 diodes type) [Copy link]

Since two op amps are used to handle the forward voltage and reverse voltage respectively, the output impedance of this circuit is very low. R1 and R2 need to be accurately matched, otherwise the circuit gain will not be 1 when the input is a negative voltage. The resistance value of R3 is not important, but it cannot be too small, otherwise U1 will need to provide a large current to R3 when the input is a negative voltage. The input impedance of this circuit is the resistance value of R2. When the input voltage passes through zero, the output voltage of U1 and U2 will change suddenly. Therefore, if the frequency of the input signal is high, U1 and U2 need to use high-speed op amps.