Which is positive, negative and ground?

 i cant figure out which prong is which just by looking and i dont have an expertise in electronics, so if you guys could help that would be wonderful, heres a pic 

Picture of Which is positive, negative and ground?
gmoon7 years ago
Typically, the outer collar or shaft of any plug is negative (ground), when translated to the jack makes #3 the ground, and the center pin #1 is positive.

The "arrow" connection between #2 and #3 is a switch--often used to switch between power supply and batteries. The circuit ground is connected to #3, and battery neg. terminal to #2. When the plug is inserted, the battery connection is broken, and the circuit draws power from the external supply.

However--Not every manufacturer uses the collar (-) / center pin (+) convention. Some specifically swap polarity to force consumers to buy their proprietary wallwart or power supply...
Re-design7 years ago
There is no standard.  You MUST check the equipment that you are trying to power and get the correct polarity if it is dc.  If it is ac there is no difference.