Amps & Volts question

[IVB]

Want to double-check an answer before I fry another camera/power supply. I haven't done anything with this amps/volts stuff since college...

I have a camera that takes 12VDC. It needs something like 80mA to run, 350mA if the IR LEDs are on.

I have a power supply that is 12VDC, and can provide up to 1.5A of power. It's meant to power several cameras concurrently.

I believe I can plug the power supply directly into the camera, b/c even though it's capable of providing 1.5A, the camera will only draw 80mA during the day.

That's correct, right?

 

[Digger]

Yes you are correct.........

Just watch your polarity and dont short your leads with the power on (make your connections with the power off etc).

Good Luck ........

 

[BraveSirRobbin]

I'm a big believer of installing in-line fuses also!

 

[IVB]

After blowing $180 on my prior camera & wart, I think that's a fabulous idea.

 

[BLH]

Some power supplies that are not well regulated. May have a higher voltage output if not loaded close to the rated output.
Than again the cameras input voltage range may not be that tight anyway.
I to like fuses.

 

[BraveSirRobbin]

Yes, that's a good point concerning wall-warts. Their actual output voltage may depend on the AC voltage input.

Mine always show almost 0.5 volts more than their specifiec DC output (due to my AC line being higher than most).

 

[Guy Lavoie]

I've noticed that most wall warts seem to put out a higher voltage then their indicated value, especially DC current ones. Some of the cheaper ones are only half wave rectified with a diode and filter capacitor, so the voltage goes down as power draw increases and gets closer to the rated output. But it still tends to appear higher, especially if you reading the voltage with a simple multimeter. A scope gives you a better picture of the output, complete with lots of ripple!

 

[Digger]

I have seen 12 Vdc output Walwarts with an open circuit voltage (no load) of close to 18 Vdc. Its usually (not always) the higher current rated units because of the way the secondary winding of the transformer is designed.

If you are going to use them for multiple cameras and have a breakout box etc you could always throw in a 12 V zener diode for a buck or two and that will regulate the voltage pretty well. Cheap and easy.

 

[TonyNo]

Don't forget about the required resistor. This was a nice Zener page.