LEDs’ Light Intensity Controller Based On PWM Technique

This project uses a classic 555 timer integrated circuit configured in an astable multivibrator mode to generate a Pulse Width Modulation (PWM) signal. The 555 timer rapidly switches its output between high and low states, creating a continuous train of square wave pulses. By integrating a 100k potentiometer and IN4001 diodes into the timing network, the circuit allows independent control over the charge and discharge paths of the 100nF and 1nF capacitors. This adjustment alters the duty cycle of the output wave—changing the ratio of 'ON' time to 'OFF' time without changing the overall frequency. The resulting PWM signal is fed into the gate of an IRFZ44N N-channel MOSFET through a 1k resistor, with a 200-ohm resistor also utilized in the gate drive path. The IRFZ44N acts as a high-speed electronic switch capable of handling higher currents than the 555 timer can supply directly. As the duty cycle changes, the MOSFET rapidly pulses the connected LED strip. Because the switching frequency is very high, the human eye does not perceive the flickering; instead, it registers a smooth variation in perceived brightness as the average power delivered to the LEDs changes.