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Sometimes
you want to slow down a brush type DC motor. The most efficient way to do this is with a
pulse width modulation (PWM) technique. The hobby circuit below can operate from about 3
volts to 15 volts. The frequency is fixed at about 2KHz but the pulse width can be
varied from nearly 100% to 0%. By using a multi-turn pot, you can accurately select the
desired motor speed. With the components indicated, the peak motor current can be about
2 amps. For higher currents, you will have to use an n-channel FET with a lower
drain to source resistance. (NOTE: This schematic was corrected 09/09/09)
Click
on Schematic below to view PDF version of this Circuit |
