information and resources on stepper motor drivers see the
The extremely simple circuit in Fig 1 drives a stepper motor directly
from 12V ac , 60 Hz power supply. Usually you need switched-dc voltages to
drive a stepper motor. But a stepper motor will run off ac lines if you
introduce a 90° phase shift between the voltages applied to the motor's two
windings. In this case only one 6.8uF non polarity capacitor is needed.
If the motor in Fig 1 and 2 moves 7.5° per step. Four steps equal one ac
cycle, so the resulting motor speed will be 300 rpm. Using other motors that
have different step angle result in different speeds.
You can run the motor off the 120Vac as shown in Fig 2 the additional
resistor is needed. The resistor's specified power dissipation and the value
of the capacitor limit the current that the circuit can deliver to the
information and resources on motor drivers see the
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