Really basic question. What is usually meant by -12VDC?
I thought that if you have a 12V battery, one end is +12V, and the other end is GROUND (-).
How can you be "below" ground? ;)
+12V? -12V?
Apr 26, 2006
6 Replies
First reply
Think of it as two 12 volt batteries in series. From the junction of the batteries (use this as the ground refferance) you will get +12 volts on one battery and -12 volts from the other battery. Some devices using intergrated circuits are set up this way. Many of the eairly…
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Think of it as two 12 volt batteries in series. From the junction of the batteries (use this as the ground refferance) you will get +12 volts on one battery and -12 volts from the other battery. Some devices using intergrated circuits are set up this way. Many of the eairly computer supplies had a -12 volt supply in refferance to the ground. The rs232 port (serial port) worked this way.
Oh! Got it now, thanks. I'd (erroneously) thought that -12V meant the negative terminal of a 12V battery.
If the + terminal is attached to ground the - terminal is then at
-12V.
Graham
A voltage never refers to "one point," unless there is a clear reference point assumed. It always refers to something of one point with respect to another, explicit or implicit, reference point.
voltage = potential difference
Best,
conect the + to ground and not the -, then the - will be below ground.
Bye. Jasen
That is the usual case that you are familiar with from cars etc however you are not limited to conecting the (-) terminal to ground/earth/chasis etc. ground is a just a usefull reference.
If you have 2 bateries in series and conect ground to the middle conection then you have both +12 and -12 available.
Colin =^.^=
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