Switches (Types, Symbol & Working) Basic Electronics
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Switches are used to turn electronic devices on or off.
We can see, this simple on off switch in our house.
The electricity coming in our home, has two terminals, phase and neutral.
To control an electrical appliance using a switch, we connect, one electrical wire directly to the appliance, and the other wire to the appliance through the switch.
When the switch is pushed downward, the appliance turns on, and the device stops, as soon as the switch is pushed upward.
This is the symbol of an on off switch.
This symbol shows the open switch position, and this symbol shows the closed switch position.
These are some of the common types of on off switches, used in electronics.
There is another type of switch, called the Single Pole Double Throw or S P D T switch.
This type of switch has three pins, the middle pin is called the common pin.
To use this switch, its lever is pushed left or right.
When its lever is pushed to the right, the common pin connects internally to the left pin, and when the lever is pushed to the left, the common pin connects to the right pin.
For example, you can control two bulbs using a single switch.
When the left bulb is on, the right bulb will turn off and vice versa.
These are some common types of SPDT switches.
It is a sliding switch, which needs to be slide to the left or right to operate, it is a toggle switch, and it is an up/ down switch.
Like the SPDT switch, there is another switch, called the DPDT switch.
Double Pole Double Throw.
This is the symbol of a DPDT switch.
This switch has six legs.
We can give name C 1 and C 2 to both the middle pins.
we will give name A 1 and A 2 to both the top pins.
we will give name B 1 and B 2 to both the bottom pins.
If we connect both the terminals of a battery to the middle pins, then both the middle pins will get + and – polarity.
Now if we push its lever downward, its common pins will be connected internally to A 1 and A 2.
And at A1 and A2 Pins positive and negative polarity will come.
When we push the lever upwards, then middle pins will be connected to B 1 and B 2.
and these two pins will get positive and negative polarity respectively.