On this mission, I’ll present you methods to design an easy LED Lamp Dimmer Circuit utilizing quite simple parts. On this circuit, initially, the LED slowly glows with rising brightness and after reaching the most brightness, the LED slowly dims its brightness and the method repeats. The idea of the entire circuit is an operational amplifier IC named LM358.


One of many major benefits of LEDs over conventional mild bulbs is that an LED will be simply managed i.e. we are able to simply change its depth. You may need already used mild dimmers however this LED Lamp Dimmer Circuit is a quite simple circuit the place a bunch of LEDs repeatedly change its depth.

By making a slight modification with respect to the ability dissipation, you possibly can even implement this circuit with high-power LEDs for real-time use.  

LED Lamp Dimmer Circuit Diagram

LED Lamp Dimmer Circuit Diagram

LED Lamp Dimmer Circuit Diagram – ElectronicsHub.Org

Circuit Elements

  • IC LM358 (IC1) – 1
  • Transistor BC547 (T1) – 1
  • Resistors (R1, R2) 4.7KΩ – 2
  • Resistor (R3) 22KΩ – 1
  • Resistor (R4) 10KΩ – 1
  • Resistor (R5) 4.7MΩ – 1
  • Resistor (R6) 100Ω – 1
  • Capacitor (C1) 0.47µF – 1
  • LEDs – 3
  • 9V Battery
  • Breadboard
  • Connecting Wires

Part Description


This IC consists of two unbiased, high-gain, frequency-compensated operational amplifiers designed to function from a single provide over a variety of voltages. Operation from cut up provides additionally is feasible if the distinction between the 2 provides is Three V to 32 V (Three V to 26 V for the LM2904), and Vcc is at the least 1.5 V extra optimistic than the enter common-mode voltage. The low supply-current drain is unbiased of the magnitude of the provision voltage.


A 3 terminal digital machine employed to amplify weak enter alerts. A transistor made up of two PN junction diode linked again to again. Transistor is of many kind viz bipolar junction transistors, Subject impact transistor and picture transistor. They’re primarily utilized in the electrical machine as of their lesser dimension in addition to mild weight.


LED stands for Mild Emitting Diode. It’s made up of semiconductor machine. When energy provide is offered to LED, electrons combine with the holes and vitality is launched within the type of mild. LED can be found in many colors like Crimson, Orange, Amber, Yellow, Inexperienced, Blue and White.  Nowadays, LED’s can be found in seen, ultraviolet and infrared wavelengths and have excessive brightness.

LED Lamp Dimmer Circuit Image 1

Working of LED Lamp Dimmer Circuit

LM358 is specially made up of a bundle which incorporates two unbiased operational amplifiers of excessive acquire. Essentially the most important attribute of this IC is that we want not to present unbiased energy provide for the functioning of every comparator until the big vary of the ability provide. LM358 will be employed like transducer amplifier or will be labored as DC acquire block and many others.

The DC voltage acquire of the LM358 IC is big i.e. 100db. Coming to the ability provide, this IC can work on the voltage variation of 3V to 32V whereas for the dual energy provide this IC work on the vary of ±1. 5V to ±16V. And furthermore, the massive output voltage can be supported by it.

Pin configuration of the IC LM358 is being described beneath.

Pin Configuration of IC LM358

Pin Configuration of IC LM358

To get a triangle wave an op-amp is used within the circuit that has been defined right here. It’s only as a result of the triangular wave that the LED begins glowing slowly and have become brighter after which slowly will get off and once more it turns into brighter slowly. The identical cycle goes on repeat most of the instances.

In every unbiased op-amp of the bundle, there are two enter pins and one pin because of the output, because it has proven on the determining above. Pin 2, which is an adverse pin and pin 3, which is the optimistic pin are the 2 enter terminals of the op-amp. For the optimistic suggestions pin, Three is used and if there’s a need of the adverse suggestions pin 2 is used. When there aren’t any suggestions given to the op-amp than at that state infinite acquire, is the perfect situation for the op-amp.

LED Lamp Dimmer Circuit Image 3

When the voltage at pin quantity 2, which is an adverse enter pin, is increased in comparison with the voltage at pin Three i.e. an optimistic pin, then the output might be obtained in the direction of most optimistic voltage whereas if there’s a slight increase on the adverse pin of the op-amp as in contrast with the optimistic pin of the op-amp than the output strikes within the course of the adverse most. This attribute of op-amp craft it acceptable for the usage of degree detection.

The voltage degree which we wish to detect is utilized to both of the enter pins and the voltage to be detected is utilized to the opposite pin. In our circuit, we’re making use of a voltage on the optimistic pin that’s at pin Three and voltage to be detected is utilized at the adverse pin.

On the occasion when the enter voltage given to the optimistic pin is a bit more than that of the voltage given on the adverse pin, at that situation the output quickly mounts to the optimistic most and reside within the optimistic state until the enter voltage drop decrease than the extent to be detected.

The identical phenomenon is getting used on this circuit too. For the timing element resistor, R5 in addition to capacitor C1 is used. State of the pin Three switches from excessive to low situation relying upon the charging and discharging of the capacitor used within the circuit and as a reference to it pin 2 of the op-amp obtains the will output. For the driving of the LED transistor T1 is used within the circuit as a sign amplifier and to guard the LED against the harm as a consequence of excessive present resistor R6 is employed within the circuit as a present limiter.



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