Many silicon diode shows at high current, direct voltage of 1 V or higher. There are some types whose power failure at currents up to 2-3 A is limited to 0.5 to 0.6 V, but even this can produce unacceptably high losses. The electronic circuit offers a possible remedy.
Cathode of transistor T1 is connected to a sinusoidal voltage source, and the anode works as reference. C1 capacitor is charged at peak value of sinusoidal voltage, though the diode D1, supplying voltage to AO even during negative alternations.
Non-inverting input of IC1 is placed at half of the peak value of the sinusoidal voltage, with the voltage divider R1-P1-R3. Due to the voltage divider R2-R4, AO potential inverting input will be higher than the non-inverting input only during positive alternations. This means that AO will bring the drain-source channel conduction of T1 when the voltage cathode tends to be smaller than the anode.
Forward voltage of the diode made with the product of the current through the FET he's in a state of conduction resistance (0.07 ohms).
Position P1 determine voltage anode - cathode that starts growing operational amplifier output voltage where conduction occurs entrance of T1. Alternations can be adjusted precisely using only an oscilloscope connected between the FET's drain and source. It will be fixed in the position in which the nominal direct current, the voltage across the FET's is as small as possible during alternations the FET drive.
Circuit current consumption is not much higher than the current supply of IC1. Although maximum supply voltage is 36 V AO, cathode-anode voltage which is the voltage "reverse" a "diode" must not exceed 20 V, which is the gate voltage - maximum permissible source of BUZ10.