hi, i m trying to get 17V through a computer power supply for my project using the -5 and 12 connections in the power supply. i m using transistors as a switch which gets its on-off signal from a PIC(programmable processor chip) through a buffer. the problem is that the transistor can not take the -5V as its gorund for some reason. i m using the tp147/142 transistors. but they dont seem to work with the -ve voltage. is there anything else i can use as a switch that can handle the -ve voltage. voltages available from the power supply are: +/- 12V, +/-5V, 3V i need 15 or greater voltage input for my solenoid to get enough power to do whatever i need it to do. what can be done?