URGENT HELP NEEDED ***********

[koolmoecraig]

Ok, so I'm no electrician. Basically I have cut the output plug off of a power transformer because i'm going to hard wire it into something. My question:

How do I tell which of the two wires that originally went into the plug is positive and which is negative? Is it safe to assume that the one with the little specification writing on it is positive?

Thanks!
Craig

[krick]

From a post about wiring a marquee light...
http://forum.arcadecontrols.com/index.php/topic,17648.0.html

...make sure you wire it with correct polarization.

The white wire goes to the wide prong.

[krick]

Wait.  I just realized that you said it was a power transformer.  This means DC power.

To tell which wire is positive and which is negative will take a few steps...

1) look at the device that the transformer normally plugs into.  It will usually have a diagram of the plug showing if the internal or external part of the plug is positive.

2) once you know this, you can use a continuity tester (or an ohm meter) on the lopped off plug to determine which wire (striped or plain) connects to the positive connector.

I assume that you could also hook up a volt meter (set on the right voltage scale)  to the wires on the transformer and then plug it in.  If it registers positive voltage, then the red probe is the positive wire.  If it registers negative voltage (or pegs the needle backwards), then you have the probes connected backwards and the positive lead is connected to the black probe.

[danny_galaga]

voltmeter

[MinerAl]

The one that tickles when you lick it is hot, the other is ground.

[SpamYouToDeath]

The one that tickles when you lick it is hot, the other is ground.

Don wick ih unwess ooh oh eh vowtajhe.