3V transistor LED blink circuit with two LEDs
Components:
Learn how to create a simple LED blinking circuit using transistors, resistors, capacitors, and a potentiometer. This beginner-friendly tutorial guides you through the process of assembling the circuit and adjusting the blinking speed using the potentiometer. Gain hands-on experience in understanding how transistors switch on and off to control the blinking of LEDs, and explore the basics of electronic components and circuit design.
1. Resistors: A resistor is a tiny electronic component that controls the flow of electricity in a circuit. It does this by resisting the flow of electrical current, much like a narrow pipe restricts the flow of water. This resistance is measured in units called ohms (Ω). These resistors limit the current flowing through the transistors and LEDs. The 1K resistors are connected to the base of the transistors to limit the current flowing into them. The 3K resistors are connected to the collector of the transistors to limit the current flowing through the LEDs.
2. Transistors (NPN): The transistors act as switches in this circuit. When a small current flows into the base (B) of the transistor, it allows a larger current to flow from the collector (C) to the emitter (E). In our circuit, one transistor is used to control each LED.
3. Electrolytic Capacitors: The electrolytic capacitor store and release electrical energy. In this circuit, they smooth out fluctuations in voltage and help stabilize the operation of the transistors.
4. Potentiometer: The potentiometer acts as a variable resistor. By adjusting its knob, you can vary the resistance and control the blinking speed of the LEDs. It’s connected in series with the base of the transistors to adjust the current flowing into them.
5. LEDs: The LEDs (Light Emitting Diodes) are the light source in the circuit. When current flows through them, they emit light. In our circuit, they blink on and off based on the switching action of the transistors.
6. Power Switch: The most basic function of a power switch is to enable or disable the flow of electrical power to the entire circuit. When the switch is in the “on” position, it completes the circuit, allowing current to flow. When it’s in the “off” position, it breaks the circuit, stopping the flow of current.
7. Power Source: This could be a battery or a power supply, providing the necessary voltage to the circuit.
How they work together:
- When the power switch is turned on, current flows from the batteries through the potentiometer.
- By adjusting the potentiometer, you vary the voltage applied to the base of the transistors.
- As the voltage at the base increases, the transistors start conducting, allowing current to flow from the batteries through the collector-emitter path to the LEDs.
- The capacitors help smooth out any fluctuations in voltage and stabilize the operation of the transistors and LEDs.
- The resistors limit the current flowing through the transistors and LEDs to prevent damage.
- As the transistors switch on and off, the LEDs blink on and off accordingly, creating the blinking effect.
Overall, by adjusting the potentiometer, you can control the blinking speed of the LEDs in the circuit. This simple circuit provides a hands-on demonstration of how transistors, capacitors, resistors, and LEDs work together in an electronic circuit.
