This is a simple PIC16C54 programmer. I've tested it on a project board, and later built it on a simple PCB. The power supply can be any dc power supply capable of supplying at least 14-15V at current of about 200mA. My 12V wall adapter was unable to supply that (voltage dropped from about 15V to 9V) so in order to test I used batteries. For the PCB version I found an adapter supplying about 17V. The maximum voltage can be up to say 25V - 78L05 has absolute max voltage of 35V. Make sure the electrolytic capacior's voltage rating is more than the input voltage. The best way to check the required voltage is to check for 13V with a voltmeter (before plugging the progammer into PC and inserting a PIC)....