The “Single LED Relay Oscillator Circuit” is a straightforward electronics project. It uses a relay, a capacitor, a resistor, and a 3.7V lithium battery to make an LED blink. It suits for beginners interested in learning how to blink an LED using a relay.
How the circuit works? When you power, the battery charges the capacitor through the resistor. As the capacitor charges, its voltage increases until it triggers the relay. Then switches states, connecting the LED to the battery and lighting it up. After switching, the capacitor starts discharging through the relay coil. When the capacitor’s voltage drops below a certain level, the relay switches back to its original state, turning off the LED. This cycle of charging and discharging continues, making the relay oscillate and causing the LED to blink on and off. This simple project helps you understand how basic electronic components work together to create a blinking LED.
By completing this project, learners gain practical skills in building circuits and a better understanding of basic electronic principles. This simple project encourages further exploration and learning in the exciting field of electronics.
Components:
![](https://learn.circuit.rocks/wp-content/uploads/2024/07/Circuit-Diagram.png)
- Relay SPDT 10A 5V
- Capacitors 2200uF 25V
- Resistor 220 ohm
- LED 5mm White
- U Jumper Wires
- Battery 18650
- Battery Holder 18650 Single
- Third Hand with Magnifying Glass Tool
- Solder Lead
- Soldering Iron
Connections:
![](https://learn.circuit.rocks/wp-content/uploads/2024/07/Circuit-Diagram-2.png)
- LED: Connect the cathode (negative) of the LED to the negative terminal of the relay coil (Coil -). Attach the anode (positive) of the LED to one end of the 220-ohm resistor.
- Resistor: Link one end of the 220-ohm resistor to the anode (positive) of the LED. Connect the other end of the 220-ohm resistor to one of the relay coil terminals (Coil +).
- Capacitor: Attach the positive terminal of the capacitor to the same relay coil terminal where the resistor is connected (Coil +). Connect the negative terminal of the capacitor to the other relay coil terminal (Coil -).
- Relay: Use a jumper wire to connect the normally open (NO) terminal of the relay to the same relay coil terminal where the resistor and capacitor are connected (Coil +).
- Battery: Attach the positive of the lithium to the common (COM) terminal of the relay. Connect the negative of battery to the negative of the capacitor or negative terminal of the relay coil (Coil -) to power it.
Notes:
With basic tools like a Soldering Iron, Solder Lead, and a Third Hand with Magnifying Glass Tool. Creating the “Single LED Relay Oscillator Circuit” becomes an easy and accessible project for beginners. The soldering iron and solder lead enable precise and secure connections between components, ensuring the circuit functions correctly. The magnifying glass tool helps in viewing small parts and making accurate solder joints, making the assembly process straightforward and efficient. With these tools, even those new to electronics can successfully build this simple yet educational project.