Working of diode as a switch in electronic circuits.

Basic circuit of a Diode as a switch

In the previous post we have seen the basic working of a diode.

Now in this post let us see how a diode can be used as an electronic switch in the electronic circuits.

Let us study the operation of diode as switch from the following circuit

In the above circuit a bulb is connected to a battery through the diode.Therefore the diode acts as either "ON" switch or as an "OFF" switch depending on biasing.

Now in the following circuit let us see how a diode is working as an "OFF" SWITCH:

As the diode positive side is connected to the negative of the battery and negative of diode is connected to positive of the diode, the diode is in reverse biased condition.

We have seen that the diode do not conducts an electricity in reverse biased condition and no current flows through it. Therefore the diode acts an "OFF" SWITCH in reverse biased condition.

The Bulb is OFF bacause the diode stops the flow of current through it and as a result no current flows through the Bulb.
Therefore the bulb is OFF and is not glowing.

Let us see how the diode acts as an "ON" switch:

As the diode positive side is connected to positive of the battery and negative side of diode is connected to negative of the battery, the diode is Forward biased.

In forward biased condition diode conducts electricity and current flows through it therefore it acts as an "ON" switch in forward biased condition.

As the diode is conducting electricity,it allows the current to flow through it and the same current flows through bulb which makes the bulb "GLOW".