# 12V - 24V (Voltage Doubler)

Discussion in 'Electronic Basics' started by Sean J, Apr 5, 2004.

1. ### Sean JGuest

If any one can help, I've run into another problem, Roland sent me this
circuit (it works fine), but it runs the battery flat quite quickly

http://www.aaroncake.net/circuits/6-12conv.htm

" I have a 12V dc car battery and I need to run some truck electronic
equipment, approx. 24V / 25mA "

I wonder if anyone can help me with a schematic of a Voltage doubler from
12V dc to 24V dc. I have seen one in a Electronic mag a long time ago. It
used 2 transistors which oscillated, and 1N4007, a cap, etc. I only need
25mA at 24V dc at the output. Please if anyone can help, I would greatly
appreciate it, thanks.

Sean

2. ### Seth KosterGuest

This is probably the circuit, or very close to it. Transistor
gate resistors both 1K, transistors both MJE3055, diodes 1N4004 (check
this, I am working from old, sketchy notes), filter cap 1000uF. If
you use the secondary of a 24V center tapped stepdown transformer
(5:1) KEEP THOSE PRIMARY LEADS SAFELY SEPERATED AND INSULATED, you'll
Basically this acts as an oscillator outputting a squarewave, then the
output is rectified back to DC.
In any case, since I am working from old lab notes, you might want
to breadboard the circuit first just to see what comes out. Some
issues that come to mind are that the filtering may not be adequate
and the diode may need to be revalued since I don't remember what my
input voltage was. I don't think the primary field had anything to
do with how the circuit works, so you might want to find or make a
center tapped inductor to avoid AC output at the primary windings of
the transformer.

------------>|-----|
| |
| |
| |
|-------------o----------- |
| | | |
| |/ VCC C| |
| |--/\/\---| +-- C| |
| | |> C| | LOAD
| | |----| | |
| | |> | | o----.----/\/\----.
--(--/\/\---| === | | | |
| |\ GND | | | |
| | | | | |
------------o----------| | --- ===
| | /-\ GND
| | |
| | | FLITER CAP
------------->|----| |
===
GND

created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de