Two way switch
Normal switch has two positions i.e ON and OFF position which allow user to control electrical loads such as lights, fan, Motor, TV etc from one place. where Two way switch allows user to control electrical load from two places. Even you can use two way switch as normal switch to control electrical loads from one place. Two way switch has 3 terminals. Extreme (end) terminals are considered as T1 and T2 . In reality there is nothing like T1 and T2 but for understanding purpose T1 and T2 is considered. You can consider any extreme terminal as T1 and T2. Two way switch button is shown in below image.
In order to control electrical load from two places you need to use Two , two way switches together. Live or AC supply (230 Volt) is connected to terminal T1 of both two way switches . Middle terminal of both the two way switches are connected to each other. Terminal T2 of both the two way switches are connected to each other . One side of load is connected terminal T2 of two way switches and other side is connected to Neutral . Two way switch connection diagram is shown below.
In two way switch there is no fix ON and OFF position. ON and OFF position is depends on how you connect the two way switch. As there are Two , two way switches there 4 different combination of switch positions which is shown in below table. Here switch ON means switch is pressed at terminal T1 and switch is OFF means switch is pressed at terminal T2.
Case 1: When both switches are at different position.
When both the two way switches are different positions, than there is a flow of current through the circuit in following path and load (Bulb) will be ON. Shown in below image.
Live – T1 – Middle terminal – T2 – Bulb – Neutal
Case 2: When both switches are at same position.
When both the two way switches are same position means either both the switches at T1 or T2 , than there is no flow of current through the circuit and load (Bulb) will be OFF. Shown in below image.