<VV> Voltage reducer / 2nd answer! ggg

[JVHRoberts at aol.com]

The problem is the load using speakers is NOT that constant. AT ALL! 
As far as parts count goes, it's one regulator chip, about $2, two  
resistors, and a capacitor, and you're good to go. 4 parts! The capacitor goes  on the 
output. You don't even need a circuit board! The only thing you need to  
figure out is the value of the two resistors to trim this thing to 9 volts, and  
the link I sent even had the formula for that. 
As an alternative, if you do an online search and order an LM7809  regulator, 
it's already set for 9 volts and all you need there is the chip one  
capacitor, and you're done. 
However, you'll need to order this one. The LM317 is available at Radio  
Shack. 
 
In a message dated 2/15/2006 11:58:43 P.M. Eastern Standard Time,  
vairmike at sbcglobal.net writes:

>The  voltage needs to be regulated. A resistor alone won't do it reliably  
and  
>safely, since the load is no doubt NOT constant! 
>   
>
Actually the load is likely more constant than the source voltage.  I 
agree a regulator is the RIGHT way to go. I could build one with only  
2-3 parts but if you are not into building electronics I would suggest  
going to Radio Shack or similar store and buy a supply that plugs into  
the lighter sicket and be done with it.

Mike  Kost