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# Changing amperage

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#### sandeep500

##### New Member
i have an old SMPS, it gives out 5V, 12V -5V etc... and i think it gives out 25amp current,
my power adapters to the cordless phone and a wireless camera are burnt, so i am planning to use this SMPS to supply power to these things.. i searches a lot on the net but got confused with those answers..
how can i lower amperage for these..??

camera- 5V 1amp
cordless phone- 9V 350mA
& 9V 210mA

If that SMPS is out of a computer, they sometimes don't work properly unless there is a minimum load connected to it. Assuming that it runs loaded or unloaded then it should work as a charger as long as you select the correct voltage output.

You seem to be confused about amperage. The current that will be drawn by your camera or phone is determined by those devices internally. If you supply them with the correct rated voltage, the current will be what ever the camera or phone require. All you have to do is to determine that the power supply will deliver at least as much current as the appliance wants.

For example, suppose you have a computer that operates on 12Vdc @ 4A and you want to run it in your car. A car battery is capable of delivering up to 1000A for short periods of time. What happens if you plug your computer into the car? It draws just 4A. The 1000A battery doesn't care that it is being asked to deliver only 4A.

It will be the same with your SMPS.

thank you for the info..
this means-'i can use the SMPS with the camera without adding anything to the circuit'

If that SMPS is out of a computer, they sometimes don't work properly unless there is a minimum load connected to it. Assuming that it runs loaded or unloaded then it should work as a charger as long as you select the correct voltage output.

You seem to be confused about amperage. The current that will be drawn by your camera or phone is determined by those devices internally. If you supply them with the correct rated voltage, the current will be what ever the camera or phone require. All you have to do is to determine that the power supply will deliver at least as much current as the appliance wants.

For example, suppose you have a computer that operates on 12Vdc @ 4A and you want to run it in your car. A car battery is capable of delivering up to 1000A for short periods of time. What happens if you plug your computer into the car? It draws just 4A. The 1000A battery doesn't care that it is being asked to deliver only 4A.

It will be the same with your SMPS.

You can sometimes solve this by connecting a small fan or disk drive along with your low-amperage load.

Last edited:
thank you...

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