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Re: [ST] Helmet cam



In your message regarding Re: [ST] Helmet cam dated Mon, 28 Apr 2003
18:44:55 +0800, Anderson, Neil G (China) said that ...

>ANG(- Mike Bostock wrote:
> 
> >I have found another DC-DC voltage regulator which supposedly
> >regulates at 12V although when tested I was getting 12.5V from the
> >regulator but 12.9V was going in.  I may try the solution with a 12V
> >Zener diode in series.
>ANG(- 
>ANG(- Sorry if you know this already but...the Zener diode would need to go in
>ANG(- parallel with the camera, i.e. from camera +12 V input to ground.  You'd
>ANG(- need a resistor between the output of the regulator and the camera/Zener
>ANG(- diode +12 V input.  The Zener and resistor can get rather warm, so it's best
>ANG(- to check the power calculations.

No I didn't know this - thanks.

Current requirement is only 130mA

What value resistor would I need?

Anywhere on the 'net I can look at some examples or has a calculator
for the values.  I did physics 30 yrs ago and my memory is a little
hazy now. 

- -- 
Mike Bostock
http://www.toothfairy.co.uk/
Wales & SW ST Riders
http://www.sprint-st.org/

'99 Red ST

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