Plug pack help

[cambee]

Hi, I want to power a camera that runs at 7 volts @ 2 amps. I can buy a plug pack (wall wart?) that is multi voltage and rated at 2.5 amps. What I want to know is: Will the camera draw the correct amperage? could I use the same plug pack on a another device requiring 12v and only 1 amp or 18v at 500mA. Is the 2.5 amps the maximum current that can be drawn upon depending on the voltage required and when a appliance says it needs a plug pack 5v @ 200mA could a power pack be used that is regulated to 5v but is 5v @ 1.0 amp? without problems? - any help in simple talk would be appreciated

[I_Daniel]

To all your questions the answer is yes for the the universal AC-DC adaptor is rated at 2.5 Amp. Since none of your requirements appear to exceed 2 Amps there should be no problems.

There is just one little catch. I have one with 3, 4.5, 6, 7.5, 9 and 12 volt switchable outputs. These are not regulated voltages and I find for instance that 6 volt is actually 9 volt, 7.5 volt is 12 volt and the 9 volt tap is almost 16 volt. From this I have gained the impression that the indicated voltages are the ac and not the dc voltages which after rectification and a smoothing capacitor the output is about 41% higher than the AC voltage. (I.e the AC voltage x 1.414 to give the peak voltage.)
But again I use it for one 555 IC devices - Dr Hulda Black and Dr Bob Beck zappers - and the current draw is in the milli-amp region. The output voltage appear to be limited by the internal resistance of the transformer since when more current is drawn the output voltage drops. (Of course this could also be because of the low MFd smoothing capacitor)

To play it safe if 9 volt is required I use the 6 volt setting. I always check the actual voltage with a volt meter.

Added as an edit: All you have to look at is that the maximum Amperes of the power supply is not exceeded. This means if using the 2.5 Amp power supply your equipment can draw anything from one milli-amp to 2.5 Amp without problems. I always use a power supply that exceeds the ampere requirements of the equipment I wish to run off it. I was once asked I have a radio that draws 1 Amp at 12.5 volt I want to use a car battery isn't it too powerful because it can deliver 60 Amps per hour. All this amounts to is the battery will last 60 hours longer before it requires recharging. When using an AC-DC convertor power supply where the Amps exceeds the requirements of the equipment it only means that your power supply will operate cooler.

[cambee]

Thank you very much, the tips were very helpful.
I measured my multi pack 3v to 12v supply and they were all off by a considerable amount as you said - so you have helped me in two areas
But - Beware - I will be back with more questions...

regards, Cambee