Forward Bias and Reverse Bias

Forward Bias And Reverse Bias

(figure 1)

1. The figure above shows a dc source across a diode. The negative source terminal is connected to the n-type material, and the positive terminal is connected to the p-type material. 
2. This connection Figure is called forward bias.
3. Current flows easily in a forward-biased silicon diode.
   

   (Figure 2)

4. Turn the dc source around and you reverse-bias the diode as shown in Figure 2. 
5. This time, the negative battery terminal is connected to the p side and the positive battery terminal to the n side. This connection is called reverse bias.

Depletion Layer Widens

1. The negative battery terminal attracts the holes, and the positive battery terminal attracts the free electrons. Because of this, holes and free electrons flow away from the junction. Therefore, the depletion layer gets wider.