On Tue, 25 Jun 2002 17:19:41 +0100 Benjamin Bromilow wrote: > I tested the resistance and it was fairly linear 0-300 ohms. The meter appears > to be moving coil/iron but it's sealed so I can't peak inside. Any ideas > on how the internals of the meter work? I'm also curious how they stop the > petrol guage from being adversely affected by the car battery voltage (9-15v).... I used to have a 1975 dodge and if you looked closely at the fuel gauge you could see it go up and down slightly. On further investigation I found an inline flasher type circuit (make and break based on heated bimetal). I was told that it was there to provide a voltage drop from 12v to 6v so the 6v guage would still work. I am inclined to believe it provided a negative temperature coeffecient to offset ambient temperature which would affect the guage since it was a bimetal type. David -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu