This circuit is intended for PWM speed control of a motor up to 500mA with the BD136, using integrated circuit 555. The capacitor must be chosen according to the motor to obtain the best performance. The transistor must be equipped with a heat radiator and for currents up to 2A we can use the TIP32. The circuit is from Newton C. Braga's Mechatronics for the Evil Genius, published in the United States.
