We can decorate different things by using LED, by adding some effects in LED lighting then it may more attractive. Here Simple Lamp Pulser Circuit designed by using dual operational amplifier LM358. By adding transistor driver and bias you can extend number of LEDs.
Here LM358 dual operational amplifiers connected in a circuit to generate triangular wave and the timing components are C1 and R4 by changing the value of these two components we can get different frequency level output. This circuit makes LED from OFF state to ON state gradually then dims gradually to OFF state.
- IC LM358 – 1
- Transistor BC547 (NPN) – 1
- LED – 3
- Resistors 4.3KΩ – 2
- Resistors 1MΩ, 20KΩ, 10KΩ, 100Ω – each 1
- Capacitor 1µF/16V – 1
- battery 6V – 1
Construction & Working
Construct this circuit from dual operational amplifier IC LM358, connect voltage divider Resistor with IC1A inverting pin 2 and IC1B Non inverting pin 5. Then connect timing Capacitor C1 as feedback to IC1B operational amplifier as shown in circuit diagram.
Output of IC1A operational amplifier is connected with IC1B operational amplifier Inverting pin through timing Resistor R4. Resistors R3 and R5 acts as feedback Resistor for individual operational amplifier.
Output from the IC1B is connected to the transistor base terminal and LEDs are connected at the Emitter terminal of Q1. When we apply voltage to this circuit it will Oscillate triangular wave depends on the timing elements value. Then LEDs are starts to Glow and dim gradually.