Positive and negative, electrical question?


#1

So a friend has just given me his hikvision door bell (similar to the ring doorbell).

He’s given me the power but he’s obviously set this up and not colour coded the connectors.

How can I tell which is the positive and which is the negative?

You can see from the pic below on has a dotted white line, just not sure which would be which.


#2

Do not connect that up to 240v what ever you do,should be more to it 12v transformer,will work any way you connect it up.


#3

That’s just the ends. Those wires come out of a plug/transformer which you cannot see in the pic.

I just need to figure out which is + and - so when I attach it to the door bell I don’t blow it up.


#4

Like Q-tip says, black is black (Bonus points to anyone getting that musical reference).

What I mean is, usually black is the negative and anything other than black is positive. This video may help if it’s the same model, shows the polarity on the back at 0:52.


#5

Cheers mate,

Just watched a video on how to use my multimeter. You are bang on the cable with the lines is the + and the black one is the -