I have designed a stepper motor and photocell circuit which will follow light when seen by the photocells. I already programed everything and am just having touble with finding a way to use the 3.5 to 4 volts from the parallel port of my computer to switch a higher voltage when needed. i do not want to use a relay (if that is what they are for). only electronics
IRL3103 FET operates on logic level input, and is rated at 30V 64 amps. IRL520 is 100V, 10A.
Both are N channel so use them on the ground side of your circuit. Are you running the motors directly from LPT1? Use snubbing diodes.