Circuit of 12V To 24V DC-DC Converter

Part Total Qty. Description Substitutions R1, R2, R3, R4, R8, R7 6 100K 1/4W Resistor R5 1 470 Ohm 1/2W Resistor R6 1 10K Linear Pot C1 1 0.01uF Mylar Capacitor C2 1 0.1uF Ceramic Disc Capacitor C3 1 470uF 63V Electrolytic Capacitor D1 1 1N4004 Rectifier Diode D2 1 BY229-400 Fast Recovery Diode See Notes Q1 1 BC337 NPN Power Transistor U1 1 LM358 Dual Op Amp IC L1 1 See Notes MISC 1 Board, Wire, Socket For U1, Case, Knob For R6, Heatsink for Q1

Notes

1. R6 sets the output voltage. This can be calculated by Vout = 12 x (R8/(R8+R7)) x (R6B/R6A).
2. L1 is made by winding 60 turns of 0.63MM magnet wire on a toroidial core measuring 15MM (OD) by 8MM (ID) by 6MM (H).
3. D2 can be any fast recovery diode rated at greater then 100V at 5A. It is very important that the diode be fast recovery and not a standard rectifier.
4. Q1 will need a heatsink.