high-frequency performance, especially for low signal levels, although an error of less than 1% at 100 kHz is possible. Similar circuitry can be used to create a precision full-wave rectifier circuit. Peak detector With a little modification, the basic precision rectifier can be used for detecting signal level peaks. In the following circuit, a capacitor retains the peak voltage level of the signal, and a switch is used for resetting the detected level. When the input Vin exceeds Vc (voltage across capacitor), the diode is forward-biased and the circuit becomes a voltage follower. Consequently, the output voltage Vo follows Vin as long as Vin exceeds Vc. When Vin drops below Vc, the diode becomes reverse-biased and the capacitor holds the charge until the input voltage again attains a value greater than Vc. References External links Rod Elliott's improved version Single op-amp full-wave rectifier circuits Analog circuits Rectifiers