slightly OT, need some electronic circuit help

[Michael Torrie]

On 10/07/2012 07:47 PM, Ryan Byrd wrote:
>> Any ideas on how to get negative volts?  I have only one power source...
> 12V positive.  
> 
> Just add another 12v DC power supply and you're good to go. Most op amps have a wide input operating voltages.
> See: http://www.sciencelobby.com/operational-amplifier/opamp-dual-power-supplies.html

I have only one power supply.  It's called a battery.  I cannot add a
second battery.  This is on a vehicle.