View Full Version : 5V Question

08-03-2008, 07:50 PM
Am I correct that there is no defined +/- on a 5V supply that you would plug into the wall? When I connect it to my BOB there isn't a specific wiring direction.

In other words pick 1 and put it on the + and put the other on the -.

Also does the low voltage side of the control system not have a ground back to the AC input or "earth"?

08-03-2008, 09:09 PM
If the wall-wart/cube supply is DC output it has a + & - connection.
They generally are isolated from ground, so if you NEED to reference it to ground, then you make a connection between - and system earth ground.

08-04-2008, 07:47 AM
I quess my problem is that the c10 BOB has one terminal marked "V5" and the other "GND" for 5 volt input to the board. How do you determine which wire is which in the wall-wart/cube supply? Does it matter?

08-04-2008, 10:38 AM
Do you have a multi-meter?
If you don't have a means to measure, and have a simple diode on hand such as a 1n4005/6/7/ etc.
You just insert the diode in series with one of the leads and the V5 term when you hook it up, the stripe end to V5 term.
If the board works, mark the diode wire +5, if it does not, reverse the leads only (not the diode) and it should now work, and now mark the wire.
Remove the diode and connect direct.
Also make sure any Wall-wart you use is DC out, some are AC, it should be marked.

08-04-2008, 09:40 PM
Got it Al. Thanks.