In this article we will discuss and learn about Electronics Circuit – LED Blink using Astable Multivibrator. This is a simple two-LED blink example using the astable multi-vibrator circuit. This circuit generates two different not-stabled state output pulses. We can connect the LED in the two output pulse points and our LED blinks easily. This follows all instructions given to help those who are beginners in electronics. if you know skip what you know already.
Contents
Video Demonstration
First thanks to Mr: Datta Benur for creating the real time application using this circuit. Subscribe YouTube Channel.
Pr-Request to lean
You want to learn how this works logically read the following first, if know already ignore and continue next
- What is an Astable Multi-vibrator?
- Resistor
- Capacitor
- Transistor
Required Components : (approximate cost : $0.93)
| LED Blink using Astable Multivibrator | |||||||
| Items | Image | Value | Required Quantity | Data Sheet | Approx Price | Buy Link | Notes |
| LED-L1,L2,L3 |  | 1.5v, 20mA LEDs | 3 | $0.06 | You can use SMD also | ||
| Transistor-Q1,Q2 |  | BC548 (NPN Transistor) | 2 | BC548 | $0.14 | Aliexpress | You can use SMD also |
| Capacitor-C1,C2. |  | 47uf 16v electrolytic capacitor | 2 | 47uf, 16v | $0.03 | Aliexpress | |
|
Resistor-R1,R2
|  | 47Ω, 0.25w 5% (Yellow, Violet, Black, Gold) | 2 | 47Ω, | $0.04 | Aliexpress | Used Carbon film Resistor. You can use SMD also. |
 | 47KΩ, 0.25w, 5% (Yellow, Violet, Yellow, Gold) | 2 | 47KΩ | $0.04 | Aliexpress | Used Carbon film Resistor. You can use SMD also. | |
| Dot Board |  | Approx 5cm x 4cm | 1 | Nil | $0.12 | Aliexpress | |
| En-closer | DIY | 6cm x 5cm | 1 | Nil |
You can make your own using sheets or Buy in Online | ||
| Battery |  | 9V, 350mA | 1 | Battery | $0.50 | Aliexpress | Used 350mA, 9v Source you can use any other power source 5-12v, min-200mA. |
| Battery Holder |  | 1 | Nil
| $ 0.06 | Aliexpress | ||
Note: This above price is mentioned at 2018-05-26 (approximate only). It may be vary when you will buy again. Project cost App : US-$1. Indian – 35rs.
Required Tools
- Hardware
- Soldering Station
- Wire Cutter or sipper
- Software Simulation (optional)
- Proteus simulator
Circuit Diagram
Note: Resistor R1-10-Ohm used because used Two LED’s (D1,D2), You can use 47Ohm resistor for one LED , Other side used R4-47-Ohm.
Simulation Output
Note: Used Proteus Simulation Tool – Version Professional Proteus 8. Proteus Project file download.
Circuit Working Explanation
- When the power ON time C1 and C2 charge same time. At that time LED1, LED2, and LED 3 is OFF condition.
- When C1 or C2 is charged full any of the capacitors discharges the charged power.
- At that time cross-coupled transistor becomes active and its like a switch, connecting the ground line to LED cathode side and the corresponding LED ON.
- Once discharged completely, that capacitor goes to charge. the parallel capacitor discharge. then time another LED will be ON.
- This process continuously does so LED will blink.
- You can change the blink time by changing the capacitor c1, and c2 values.
Real-time application
- Timer Module
- Police Light
- Emergency vehicle Light