LED dimming circuit controlled by NE555

Wide modulation: The dimming method of LED is to use pulse width modulation (PWM)

LED dimming circuit made with NE555

This circuit can be easily made, with the 12V DC power supply shown above powering the LED bulbs and dimming 9 LEDs through the NE555.

The transistor in the circuit diagram is an NPN transistor , which must be able to withstand all the current flowing through the series of LEDs.

When we tested the circuit, the resistors in the LED string were chosen to provide a forward current of 25mA for the LEDs . The current of the three sets of LEDs is 75 mA, so we chose a transistor with an IC rating of 200 mA (BC547), or you can choose one with a larger circuit.

This dimming circuit cannot be used to make all LEDs off or at full brightness. In fact the NE555 operates in the same duty cycle range of 5%-95% with the potentiometer (P1) turned on from minimum to maximum.