green is ground regardless of ac or dc
A: No problem but don't expect the power to increase
If it is DC then red is positive and black is negative.
LED's are DC voltage. Transformers are AC voltage. There is no positive or negative on AC voltage. You would need a diode to change the AC to DC, then there would be positive and negative voltages.
conclusion of dc power supply 9V
AC currents alternate from AC to DC in a constant wave. The DC current is a direct and consistent current demonstrated to the negative reading. AC traveling from negative to positive and DC traveling in negative.
Yes, the electrode holder (stinger) is positive and the ground is negative which means you would be welding DC positive.
There's no such phenomena as negative DC. Minus sign only means, that current is flowing the other way than you are measuring. It's danger is exactly the same as "positive" DC.
No. 9 v is only 75% of 12 v.
If you are referring to using a volt meter then you will just get a negative reading on most modern digital meters. If you are using an old analogue meter you may get no reading.
you can take a 9v batt and tap it to your speaker wire. Hold one wire to a terminal on the 9v and tap the other on and off the opposite terminal if the speaker pulls in wrong polarity if the speaker pushes out its correct. Then just make note of which one was on which terminal of 9v and your good to go
It travels from negative to positive. The opposite of what you might think.