This kit is a very useful circuit for driving 5, 6 or 8-wire unipolar stepper motors. It can operate either freestanding or PC-controlled. The circuit and stepper motor may use separate supply voltages. Four high current IRFZ44 MOSFETs are used at the output. The motor can either be stepped by the internal, variable oscillator or by external 5Vp-p pulses. The direction of rotation can be set with a switch. This innovative circuit only uses standard CMOS ICs 4013, 4030 and 4093. Full explanations are given.
- Supply Voltage: (kit) 7 - 12Vdc (stepper motor): 8 - 35Vdc
- Supply Current: (kit) 0.1A max. (stepper motor): 6A max. per winding
- Dimensions: 46 x 75mm, 25mm height
In free-standing mode an internal square-wave oscillator based on IC2:B of the 4093 supplies timing pulses to the OSC output. The frequency of these pulses and thus the speed of the stepper motor is controlled by the trimpot VR1 (100K.) A series 1K resistor controls the maximum frequency. You may increase the value of this resistor for your own needs. These pulses are fed into the STEP input which is buffered and inverted by IC2:D. This helps prevent false triggering. Similarly, IC2:C buffers and inverts the DIRection input. A SPDT taking the input to +5VDC or ground controls the direction of rotation.