I have a device that uses 12vdc and 120ma. If i supply the device with a transformer that produces 500ma @12vdc, will this damage the device?
ex: My cctv camera consumes 120ma @12vdc. my transformer produces 500ma.
check the device datasheet for the Imax of dc specification Generally, a larger current is most likely to damage the device.
check the device's datasheet for the Imax of dc specification Generally, a larger current is most likely to damage the device.
Possibly, but not likely. A car battery can deliver hundreds of amperes but it doesn't blow out the dome light.
The only risk is that the supply is very poorly regulated and the voltage will rise when it is under loaded. I would want to check the voltage out of the supply when I loaded it with a dummy load, like a
12 volt lamp that is rated for about 120 mA.I doubt the camera need precisely 12 volts, but I don't know exactly what range of voltage it can tolerate.
It will be ok.. the device only draws what it needs. As long as your supply has enough that your device needs it will work.. Its like asking my house ac power can supply 200 amps and my light bulb only needs 1 amp. It will only use 1 amp even though it has 200 available. This is I hope just to make the point, since to have 200 amps available at once, the light would need to be directly connected to the main breaker. Just hope the transformer ( wall wart ) , is filtered so your camera dont have noise in its picture. jim...
Look at it this way, the power supply can supply up to 500 mA if the load requires it.
To suggest "Generally, a larger current is most likely to damage the device." would not make sense. For examples - the battery in your car can supply perhaps 50 Amps and its not going to damage a dome light that pulls less than one amp, or the 15 Amp A/C line in your house is not going to damage a 7 watt night light bulb that pulls only 6/100ths of an amp.
Ah, yes, from the load perspective, the value of load and output voltage determine the output current. I just confused actual output current with the drivering capablility of the transformer. thanks
Mr. Popelish was correct -- there is some small chance that an unregulated wall wart would damage a low load device, because at low loads an unregulated supply delivers a higher voltage.
Yes, you should have higher current rating to support your device. Higher current supply rating will not destroy your device easily unless it is not properly regulated. Higher current rating means that it can support high power consumption devices. I recommend current rating double to what you want to drive.
Note that voltage needs to match to your device. Over voltage supply to your circuit will generate more current, which can destroy your device. For more information on the voltage variety your device can take in, refer to it's datasheet.
-- Best Regards, Lim Siong Boon
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