DC motor speed control using IC555

Circuit Description:

1. IC 555 Timer (Astable Mode):
   • The 555 timer is configured in astable mode to generate a PWM signal. The frequency and duty cycle of the PWM signal are controlled by external components.
2. Potentiometer (Variable Resistor):
   • The potentiometer is used to vary the voltage at the control pin (Pin 5) of the 555 timer, adjusting the speed of the PWM signal and, consequently, the motor speed.
3. NPN Transistor (e.g., BC547):
   • The NPN transistor acts as a switch controlled by the PWM signal. It is used to amplify the PWM signal and drive the DC motor.
4. Diode (1N4001 or similar):
   • The diode is connected in parallel with the motor to protect against back EMF generated when the motor is turned off.