How To Make Fading LED Light using NE555
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We have seen some electronic toys, LED strip light, and some lighting decoration products where LED light intensity continuously increases and decreases, it’s called Fading LED Light. Here we are going to show you how to make Fading LED Light using NE555 timer IC.
The key components of this project are the NE555 timer IC, capacitor, transistor, and LED. When we will turn on the power supply of the circuit, then the timer IC starts providing output for a few milliseconds. At the same time, the transistor is turned on to turn on the LED, and also the capacitor store some charge. When the IC stops providing the output this time capacitor starts discharging through the LED. This way LED gives us a fading effect.
Block Diagram of Fading LED
|NE555 Timer IC||1|
|100K ohm Resistor||1|
|330K ohm Resistor||1|
|47uF Electrolytic Capacitor||1|
|LED Red (you can choose any color)||1|
|PCB Zero board||1|
|Connecting wires||As required in the circuit diagram|
|Power Supply 9V (9V Battery + Battery Cap)||1|
Circuit Diagram of Fading LED
First of all, IC NE555 Pin 1 is connected to the Vcc ground (-) terminal of the power supply. IC Pin 2 is bridged with Pin 6 and connected to the positive (+) terminal of the 47 µF Capacitor (C1). Pin 3 is connected to terminal 1 of the resistor (R1). Terminal 2 of the resistor (R1) is connected to the base terminal (1) of the transistor. The node point (N1) is connected to the junction point (J1). IC Pin 4 is bridged with Pin 8 and connected to the positive (+) terminal of Vcc. Transistor emitter terminal (2) connected to the positive terminal of the LED through the resistor R2. Finally, the transistor collector terminal (3) connected to the Vcc positive terminal.
Fading LED Light Working Principle
First of all, we should understand about 555 Timer IC. NE555 timer IC used in various applications and projects. The 555 timer IC operated in three different modes such as Astable, Monostable, and Bistable Mode. Here IC operates as Astable mode. In this mode, 555 timer IC’s output pin (IC pin 3) produces square waves which used to turn ON/HIGH and OFF/LOW a load at specific intervals. We also use a BC547 transistor. It is an N-P-N transistor. We can use this transistor in two way first one as a Switch and another one as an Amplifier. Here we are using the transistor as an amplifier, which amplifies the current.
In this circuit when the IC output pin 3 goes HIGH, then the transistor starts working and amplifies the current. This current goes into the 47uf capacitor and charge this capacitor to the 2/3 Vcc, at the same time LED glows. After this process, output at PIN 3 becomes low, the transistor becomes OFF then the Capacitor start discharging up to 1/3 Vcc through the collector-emitter junction. At the same time, the LED starts fading. Then again, PIN 3 goes high, and capacitor charges and LED become glows.
Similarly, we can use different values of the resistor or capacitor for modified the rate of the LED fading in and out easily.