Converter 12 to 24VDC
This is DC to DC converter can provide up to 24V from a 12V volt DC. It can be used to run radios, small lights, relays, horns and other 24V accessories from a 12V vehicle with a maximum draw of about 800mA. It can be used to charge one 12V battery from another, or step up the voltage just enough to provide necessary overhead for a 12V linear regulator.
Op-amp as a squarewave oscillator to ring an inductor and another op-amp in a feedback loop, it won't drift around under varying loads, providing a stable 24V source for many applications. With a wide adjustment in output this circuit has many uses.
Note:
- R6 sets the output voltage. This can be calculated by Vout = 12 x (R8/(R8+R7)) x (R6B/R6A).
- 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).
- 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.
- Transistor Q1 will need a heatsink.
List component
R1, R2, R3, R4, R8, R7 6 100K_____1/4W Resistor
R5_______________________470 Ohm 1/2W Resistor
R6_______________________10K Linear Pot
C1_______________________0.01uF Mylar Capacitor
C2_______________________0.1uF Ceramic Disc Capacitor
C3_______________________470uF 63V Electrolytic Capacitor
D1_______________________1N4004 Rectifier Diode
D2_______________________BY229-400 Fast Recovery Diode
Q1_______________________BC337 NPN Power Transistor
U1_______________________LM358 Dual Op Amp IC
L1_______________________ See Notes
