Difference between One-Way Switch and Two-Way Switch

A switch is the most common device used in everyday life for turning on and off the electrical appliances. A switch can make or break a circuit. The electric current can flow in a circuit till the switch is in ON state. The switches are commonly used to turn on and off various electrical appliances like fans, lamps, coolers, ACs, etc.

There are a number of switches available, but in this article, we will only discuss about the one-way switch and two-way switch and the key differences between the one-way switch and two-way switch.

What is a One-Way Switch?

A one-way switch is the one which has two terminals and allows the current to flow only in one direction, i.e. in the reverse direction, it does not conduct. Therefore, a one-way switch makes or breaks an electric circuit by using two terminals. When the one-way switch makes the connection, it is said to be in ON state and the current flows through it. When the switch is in OFF state, it breaks the circuit and no current flows through it.

The one-way switches are employed in the applications where an electric appliance need to be controlled from only one location. The one way switches are common used in houses, offices, industries, etc. to control the operation of fans, lamps, coolers, ACs, etc. from a single location.

What is a Two-Way Switch?

A two-way switch is a type of switch which has three terminals. Basically, a two-way switch is a combination of two one-way switches in a single unit. The two-way switch can conduct in either directions.

When a two-way switch conducts, one terminal is connected to another, but the third terminal has a broken connection, i.e. all the three terminals of a two-way switch cannot be connected together simultaneously.

The two-way switch is a special type of switch, which is not commonly used. It is mainly used in staircase wiring, long corridor wiring, etc. for controlling the lamps. A two-switch can also be used to control a single electrical appliance from two different locations.

Difference between One-Way Switch and Two-Way Switch

The key differences between a one-way switch and a two-way switch are highlighted in the following table

Basis of DifferenceOne-Way SwitchTwo-Way Switch
DefinitionA type of electric switch which has two terminals and is used to conduct current only in one direction is called a one-way switch.A two-way switch is the one which has three terminals and can conduct current in either directions.
Circuit symbol
Number of terminalsOne way switch has two terminals.There are three terminals in a two-way switch.
WorkingA one way switch makes or breaks an electric circuit to operate an electric applianceIn a two way switch, two terminals are connected at a time to operate an electric appliance, and the third one is left open.
ON and OFF positionsA one-way switch has definite ON and OFF positions.The ON and OFF positions are not specific in case of a two-way switch, it depends upon the connection of the switch.
Circuit complexityThe circuit of a one-way switch to control an electric device is simple.A two-way switch involves a relatively complex circuit than a one-way switch.
CostA one-way switch is cheaper.A two-way switch is costlier than a one-way switch.
Installation cost and timeFor one-way switch, the installation cost and time required is relatively less.The cost and time required for the installation of a two-way switch is more.
ApplicationA one-way switch is mainly used in applications where an electric appliance needs to be controlled (ON and OFF) from a single location only.A two-way switch finds applications in the electric circuits where a single appliance required to be operated from two different locations such as staircase wiring of a lamp.


There are many types of electrical switches available. Two of them are one-way switch and two-way switch which are briefly described in this article. Also, we have discussed various noticeable differences between them. The most significant difference between these two types of switches is that a one-way switch has two terminals and is used to operate an electrical device from a single location only, whereas a two-way switch has three terminals and is used to control an electrical device from two different locations.