Can't find out the polarity of my bullet cam, its a sport-cam 480 line one with a 1/3" sharp CCD.

From what I can find it seems most use the middle of the power jack as positive.

Also what range of voltage can they take, on the website they sell battery packs from 9.6v up to 12v along with a cigarette socket adaptors for in car meaning around 14v.

Surely if you put a volt meter on the power supply if the polarity is correct it will read +12v
If it is wrong it will read -12v.
Steve.

What not ask the manufacturer or reseller?
Mac

I am not sure about the polarity but I can check when I get home tonight. The cam can quite happily run of the car 12v supply and I have been assured by the supplier that the cameras can cope with the changing voltage.
Dave

Seller is either slow or isnt answering emails at the moment. I havent got a power pack, you can get them cheaper from elsewhere, but wanted to check the polarity is the same. Was thinking about wiring it straight to the car if it can take the higher voltage so would need to know the polarity for that.

Google produces supply 9 to 12V DC but no indication of polarity. It's almost bound to be +V to supply and 0V to ground / case, so measure ohms fron both sides of power connector to shield of video out connector ( assuming it's something like a phono plug) or some obvious metal case bit

The side that's 0 Ohms is the negative and the side that's a hundred or so ohms is the supply.

BUT because of the strange way ohm meters work, best to measure with the red lead to shield/ground and the black one to the power connector.

I would make up a regulator from Maplin to give you +10V from the car supply.

Just checked my bullet cam. The centre pin is +ve and the outside case is -ve.

Dave