is this the place for a newbie question?

Apr 09, 2006 2 Replies

I have changed a 3 phase motor to operate as a stepper. I now want to control it from the printer port of my computer, the programming of the port is not the problem for me, I am looking for help with the electronics, What would you suggest as a circuit to control 5v input from the port to 56vdc output? I have tried relays but they are too slow to get the stepper to the speed I need. Would I be correct to say I need to use (is the word) descrete components? Cheers to you all in anticipation of your help


You need a transistor. A discrete component is just a "not inside an IC chip" thing.

An example setup with a NPN transistor:

+5V to base (resistor may be required) +56VDC to motor to collector Common GND to emitter

Someone else might suggest a part number.

How much current draw will your motor need? You may be able to get by with a uln2023a high voltage/ high current driver type chip if the current is low enough. It can switch loads at 95 volt from ttl inputs. I have a drawer full of em if you can't find any..

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