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idleup 05-04-2013 02:21 PM

Stupid Question...
Is -12v the same as ground? I am looking at my Gretz GA-1000 Heated Pitot wiring and it shows -12v and +12v...

RV10inOz 05-04-2013 02:37 PM

If you ask me it should be called ZERO VOLTS as the GND and 0v are tied together the potential between the airframe and the NEG/GND is supposed to be 0v.

Thus the airframe is GND and the battery -ve terminal is 0v and the other terminal is +12v or +24v in some systems.

you should not have -12v as the terms suggests that you could have a real -12v and that would mean 24v to the +12v.

Maybe I am wrong here.....but Ov and 12v or 0v/24VDC is what we use in the industrial world.

Jeff A 05-04-2013 02:46 PM

Not the best terminology, but in this case, yes -12v is the same as ground. Read the last line of page 1 and the first 2 lines of page 2. It clearly states -12v going to ground.

idleup 05-04-2013 03:53 PM

Thanks guys.

jim plaster 05-05-2013 11:44 AM

Check me if i'm wrong here ....but the only stupid question is the one that's never asked! Don't be afraid to ask here,we all have at one time or another!

idleup 05-05-2013 11:55 AM

Yea, what confused me is that I have always learned that negative voltage is very different than ground and ground should not be designated like that

airguy 05-05-2013 12:31 PM

And for those of us "old-school" guys that received physics/electrical education 25+ years ago, the whole idea of power flowing from positive to negative is just WRONG - it's the electrons flowing from negative to positive in the metal that does the current delivery, but most people have trouble wrapping their heads around that. Electrical convention is thus to show power as flowing from positive to negative when in reality the opposite is true.

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