Thu, 30 Sep 1999 14:26:51 +0200 - Message No. 6400
From: Michael Dipper

Subject: Re: intercom 9v/12v


Hi,

On Mon, Sep 27, 1999 at 10:08:11PM +0200, Nicola Moretto wrote:

> I'm looking for an help for this "little" problem:
> (Micha, always little problem ;-))
>  
> I want to connect my 9 volts (actually battery powered) intercom to my
> @'s battery (under key switch for avoid empty battery if I forget it
> on).
> You know @'s voltage is 12v: any idea for reduce it to 9v between + and
> - of my intercom (without damage the @'s electric circuit) ?
> 
> If you've suggestions or simple electronic circuit please let me know

Just a "little" answer :-)

Buy an IC 7809 - should be available at every electronics store
for less than 1,-- EUR.
Eventually add a small cooling fan or use the stronger S-Type.

PIN usage (front view - fan at top):

     | O |
     |---|              O hole
     |***|              * printed text
     |***|
     |---|
     | | |
     | | |
 
  12V in - ground - 9V out


Hope that helps, 

--- Micha ---

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