The precision rectifier, A.K.A. super diode. It uses two op-amps, two diodes, a bunch of resistors and a capacitor to rectify the 230VAC (rms) input, to a steady 12VDC output. This rectifier has a real steady output, no peaks like a normal rectifier which uses diodes and a capacitor. That's why it's called a precision rectifier. Used when a really steady signal is needed.
When it's switched on, it will take a while to reach the steady 12VDC.
