Electronic Devices - Semiconductors - Discussion

Diodes conduct current under forward bias because in forward bias the cathode of the diode is connected to negative terminal of a current supply source whiles the anode is also connected to the positive terminal of that source. So in this case electrons in the n side are excited across the PN junction leading into the p side where the combine with the holes. As the electrons combine with the holes, light photons are emitted.

And for diodes if the current is small diode does not work but if the current is more diode works and it the current is too much diode blows.

In avalanche condition, the electron has to overcome the potential barrier between bands to start conduct, that means more minority carriers are required to overcome this energy gap.

In saturated conditions, even on increasing the conduction electrons (increasing applied voltage) it remains constant. It doesn't increase.

So, there are some limiting values for the flow of current unlike forward bias condition.

Forward bias means anode of the diode is connected to the positive terminal and cathode of the diode is connected to the negative terminal, as a result of which more electrons are supplied 4m the negative terminal (i.e. 4m cathode to anode) and are attracted by the +ve terminal of the battery....this leads to the flow of current from anode to cathode and hence diode conducts.

If we see the internal connection of the diode there will be a resistor in forward direction it will be less so it will conducts that means short and in case of reverse bias there will be infinite resistance so it does not conduct that means open.

Because, during forward bias diode will act as a short circuit line. So that it can conduct current but in one direction. In reverse bias diode takes open circuit. There is no conduction of current.

Avalached.

Please explain one more I didn't understand. Because of reverse bias it increases minority carriers n it will over come the barrier potential and destroyed the PN junction is it correct.

When diode is forward bias the depletion layer is vanished & holes & electrons combine at the junction therefore there are will be a current from p to n direction.

In forward bias, the electrons attracted by the positive terminal and holes are attracted by negative terminal so conductivity more as compared to reverse bias.

Electrons are attracted by the positive terminal &holes are attracted by negative terminal so conductivity is more in forward bias.

Normal working condition of diode is nothing but the forward bias condition and the diode conducts in forward bias condition.