If you have a computer power supply the box type i mean those that are around 6" X 6" X 3" or so in size. well some of them can be made variable as long as they have a TL494 or KA7500 voltage regulator. if you find one of these I will give you some information how to convert it in a variable power supply from 1 to around 30 volts and a variable constant current from 0.1 to 10 amps depending on the ATX power supply capabilities.
Regards
Silvio
Regards
Silvio