# Getting 1.2v out of 12v the easy way

Discussion in 'The Projects Forum' started by jj_alukkas, Jun 11, 2010.

1. ### jj_alukkas Thread Starter Distinguished Member

Jan 8, 2009
752
7
I have a rotating pendulum and wish to run it on my car battery. And using regulators and stuffs to get 1.2v is not worth the work done. So could anyone suggest me the easiest way to get 1.2v out from 12v??

Also will this work? If so, what resistor??

File size:
13.5 KB
Views:
93
2. ### SgtWookie Expert

Jul 17, 2007
22,194
1,764
How much power or average current does your pendulum require?

3. ### John P AAC Fanatic!

Oct 14, 2008
1,671
241
Yes, whether that two-diode setup is workable depends on how much current you're going to need. Also, how much accuracy do you need in the voltage? You can't just say "a diode has a 0.6V drop" and act as if it's true, unless you're not at all fussy about the voltage.

4. ### jj_alukkas Thread Starter Distinguished Member

Jan 8, 2009
752
7
Measured the current and seems to draw somewhere varying between 1-3mA. It was designed to run off a standalone AA battery, so consumption is low I think. It has a two transistor multivibrator setup and a dual coil on same core inside. Voltage I guess can be from a little over 1v to maybe 3v. Atleast above 1v is required to run 2 trans's right?

5. ### SgtWookie Expert

Jul 17, 2007
22,194
1,764
See the attached for a simulation.

I1 is a pulsed current load of 50mA for 5mS every 100mS (1/10 second). I don't know what your actual load or frequency is. C1 acts like a small battery when the load turns on, and R1 charges it back up until the current drain from D1/D2 clamps the voltage on C1.

File size:
51.3 KB
Views:
46
6. ### jj_alukkas Thread Starter Distinguished Member

Jan 8, 2009
752
7
Thanks SgtWookie..!! I'll try it out..