Unipolar Stepper Motor Driver Circuit

This page presents a circuit for driving high-power unipolar stepper motors. Here you will find all the information needed to make your own. This circuit allows step-level control and can be easily modified for other modes of operation.

What you need

• Power
  • +5v (low power)
  • +12v (high power)
• ICs
  • L297 Stepper Controller
• Discrete Components
  • (4x) 2N6045 NPN Darlington Transistor
  • (8x) 1N4001 Diodes
  • (2x) 3.3kOhm Resistors
• Other
  • PC104 or High-Level Controller
  • 12v Unipolar Stepper Motor

Circuit Schematic and Photo

The L297 has several inputs that can be generated by a PC/104 stack or other controller. This circuit allows you to control each step, in full-step mode. Meaning: You can tell it to move one step in either direction (of course you can make it move fast and it will continuously rotate). The two inputs are a direction and a pulse. In the next section you will find a program to control this using xPC.

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