Introduction: Two Auto-OFF Timer Circuits || 555 IC or Transistor

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The Timer circuit turns ON when connection is given and turns OFF automatically after few seconds, depending on the value of Capacitor used in the circuit.

Here, I will show you two different ways to make this circuit using :

1. 555 Timer IC

2. Transistor

Pushing the push button switch turns ON the output (LED), which then turns OFF automatically after few seconds, influenced by the capacitance used.

Step 1: Components Required

These are the Components Required for making the circuit:

1. Using 555 Timer IC ()

• 555 Timer IC

• Momentary Switch

• Resistors: 47 K Ω, 330 Ω

• Capacitor: 100 μF

• LED

2. Using Transistor ()

• Transistors: BC 547

• Momentary Switch

• Resistors: 10K, 330Ω

• Capacitor: 100 μF

• LED

Other Requirements :

• Battery: 9V and battery clip

• Breadboard

• Breadboard Connectors

Step 2: Circuit Diagram

These are the Circuit Diagrams for making the circuit using :

  • 555 Timer IC
  • Transistor

Step 3: Step-by-step Tutorial

This video shows step-by-step, how to build all these circuits.