# +(x)V and 0V

Discussion in 'Hobby Electronics' started by simon, Dec 23, 2004.

1. ### simonGuest

Hi there,
on many electronic circuits i see +x amount and 0V what do i put in the 0v

ie i see a circuit with 12v+ and the other with 0v do i run a +12lead to the
+ and leave the 0v or do i put the - in there

my electronics teacher wasnt very clear

thanks alot

2. ### Rheilly PhoullGuest

If it's a 'single' supply ie. a single plus voltage and a negative (like a
single battery cel) then connect as you say, if it's a 'dual' supply ie.
+12v, 0v, -12v then the common point or ground is usually the 0v and there
are two other lines, one is 12v positive to 0v or ground and the other -12v
to ground. This type of supply is used a lot with op amps etc.

3. ### Fred FerdGuest

Ok, clearly you can work out where the +12v supply lead goes, so connect
that to the circuit at +12v.

The battery has + and - terminals. So we will say that + is +12v. Now the -
of the battery is negative compared to +. that is ([email protected] minus
[email protected] ) is negative. So that means the -ve of the battery is actually
0v or ground on the circuit.

If you have a + and - power supply, then you have +12v , 0 (which may or may
not be grounded) and -12v.

The difference between the +12 and 0 terminals on the power supply is 12
volts,
The difference between +12 and -12 terminals on the power supply is 24
volts.

Its important to remember that the +12 and -12 are only +12 and -12 relative
to the 0 terminal on an isolating power supply. (some power supplies may
have 0v connected to ground INTERNALLY, it its not isolated properly.)

If 0v is grounded, then the +12 and -12 are +12 volts and -12 volts
relative to ground and to the 0v terminal.

4. ### NathanGuest

hi there thanks both for your help,
sorry i did not reply earlier i have been away

thank you
nathan  