Three Push ON – Push OFF Latching Circuits

A flip-flop or latch is a circuit that has two stable states and can be used to store state information. The circuit can be made to change state by applying a signal (in this case, by pushing a button).

Here, I will show you three different ways to make latching circuits:

  1. Using 555 Timer IC
  2. Using Transistors
  3. Two Switches

I will also show you how to toggle between two outputs (by using transistors), using a single push button switch.

Pushing the push button once turns ON the output (LED), and pushing it again turns it OFF.

You can also use separate Push Buttons to switch ON and OFF the load.

Step 1: Circuit Diagram

These are the circuit diagrams for:

  • 555 Timer IC
  • Toggle Switch
  • Transistors
  • Two Switches

Step 2: Components

These are the Components Required for:

1. Using 555 Timer IC

• 555 Timer IC

• Push Button Switch

Resistors: 100K, 10K (2), 330Ω

Capacitor: 1 μF


2. Using Transistors

Transistors: BC547 (2), BC557

• Push Button Switch

Resistors: 1M, 470K, 220K (2), 100K (2), 10K, 1K, 330 Ω

Capacitor: 1 μF


3. Using Two Switches

Transistors: BC547, BC557

• Push Button Switches (2)

Resistors: 10K, 1K (3), 330 Ω


Other Requirements:

• Battery: 9V and battery clip

• Breadboard

• Breadboard Connectors

Step 3: Step-by-step Tutorial

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



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    4 months ago

    Interesting. I hadn't seen latching circuits using just transistors before. Thanks for sharing.