Transistor as a Switch(STEAM Education)

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To understand how a transistor works as a switch.

Project : 33

Transistor as a Switch

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Project Aim:

To understand how a transistor works as a switch.

Components Used:

1. Power Supply

2. Transistor NPN

3. Push Button

4. LED

5. Resistor 220Ω & 1K

6. Connecting Wires

Circuit Diagram:

Connection Procedure:

Step 1: Connect the positive terminal of the power supply (Pin 62) to one end of the push button (Pin 57).

Step 2: Connect the other end of the push button (Pin 58) to one end of the 1K ohm resistor (R3, Pin 5).

Step 3: Connect the other end of the 1K ohm resistor (R3, Pin 6) to the Base of the Transistor (Pin 30).

Step 4: Connect the Emitter of the Transistor (Pin 29) to the negative terminal of the power supply (Pin 59).

Step 5: Connect the collector of the Transistor (Pin 31) to the cathode of the LED (Pin 44).

Step 6: Connect the positive terminal (Pin 62) of the power supply to one end of the 220Ω resistor (R2, Pin 3).

Step 7: Connect the other end of the 220Ω resistor (R2, Pin 4) to the Anode of the LED (Pin 43).

Step 8: Press the push button to allow current to flow through the circuit, activating the NPN transistor and causing the LED to light up.

Explanation:

Transistors are essential components for both switching and amplification tasks. Unlike traditional relays, transistors offer enhanced reliability and cost-effectiveness due to their solid-state nature. Operating in three modes - Active, Saturation, and Cut-off - transistors facilitate switching operations across these regions.

In this project, we demonstrate the transistor's switching capabilities by connecting it to a battery and LED. Initially, when power is applied at the transistor's base, it remains in the cut-off region, yielding no output. As the base voltage increases, the transistor transitions to the active region, enabling the LED to light up. Finally, as the base voltage further rises, the transistor enters saturation, maintaining a constant output regardless of further supply changes. Through this experiment, we explore the transistor's dynamic behavior as a switch, enhancing our understanding of its operational principles.