What is a switch?
You return home after a tough day at school. As you enter, you dash to your room, almost throw your bag on the floor flip the switch on the wallet voila! The generous fan readily fills the entire room welcoming coolness. That is the magic of one flip of a switch. But what is it, anyway?
A switch is one of the most basic, but VERY important components in a circuit.
When the switch is open, the circuit is broken, and no current will flow through it. When the switch is closed, the circuit is closed or made, and therefore, current will flow through it.
Types of Switches
Broadly, switches can be divided into two types:
- Mechanical switches: Mechanical switches work only when someone or some external force actives them either by moving, touching, pressing, or releasing its contacts.
- Electrical switches: Electrical switches do not require anybody from the outside to activate them. They are actually electrical components that generally turn ON or OFF depending on the current flowing through them.
We will be focusing our attention on mechanical switches. They can broadly be classified into two types:
Maintained Switches:
These switches stay in one state i.e. either ON or OFF, unless the state is changed by someone. E.g. the wall switches that let you feel the cool air of your AC as soon as you flip it to its ON state.
Momentary switches:
These switches stay in a state i.e. either ON or OFF, as long as they are activated. They come back to their original state once they are released. E.g. the keys on your keyboard. They remain activated, i.e. they type the specific character for as long as you press them. Once you release the key, they don’t type anymore.
The switch that we’re going to be working with is a momentary switch and is called tactile switch. A tactile switch is a simple momentary switch which is ON only when the button the pressed. As soon as the button is released, the switch returns to its original state, i.e. the OFF state.
Now, it’s time for some learning by doing! Let’s make a small torch using the same LED that we used that turns ON only when we press the tactile switch.
What you’ll need:
- An LED
- A 220Ω resistor
- Two male-to-male jumper wires
- A tactile switch
- The powerhouse: evive
What you must do:
- Like before, take the tactile switch and insert it across the gap in the middle of the breadboard.
- Then, take one of the jumper wires and connect one of its ends to the 5V pin in the ANALOG IN pin stack above the breadboard. Insert the other in the 1st column of the 1st row of the breadboard.
- Next, take the 220Ω resistor and insert one of its legs in the 1st column, right below the jumper wire i.e the same column. Take its free end and insert it in the same row.
- Now, take the LED and insert its positive terminal in the same column as the resistor, i.e. the 1st column in the 1st row from the bottom. Then, take the negative terminal and insert it in the same row, but in that column in which the lower/second left leg of the switch is inserted.
- Next, take the second jumper wire and insert one of its ends in any row, but in the same column in which in the lower/right leg of the switch is inserted. Then, take the free end and connect it to the GND pin in the pin stack above the breadboard.
- Finally, switch evive ON. You’ll observe that unless you press the switch, the LED will NOT glow. This is because the switch is OPEN, and as a result has broken the circuit. Once you press, the LED will glow, but only till the time you keep the switch pressed. As soon as you release it, the LED also stops glowing.
Below is the complete circuit: