Name: Energy Band Gap
Uploaded: 2019-07-19
Duration: 5 min 21 s
Description: We know that certain materials conduct electricity whereas some don’t. Has it got anything to do with their energy bandgap? Let’s find out in this video.

Question

Define the term 'depletion layer' and 'barrier potential' for a

P - N

junction diode. How does an increase in doping concentration affects the width of the depletion region? Draw the circuit of a full-wave rectifier. Explain it's working.

Accepted Answer

(a) Depletion layer is the region created around the p-n junction which is devoid of free charge carriers and has immobile ions.It is created due to diffusion of majority carriers across the junction when p-n junction is formed.

Potential barrier is the potential difference or junction voltage developed across the junction due to migration of majority charge carriers across it when p-n junction is formed. It opposes further migration of majority carriers across the junction due to this junction voltage.

(b) If we increase doping, the number of majority charge carriers (holes on the p-side and electrons on the n-side) will also grow. This would result in an increase in the breadth of the depletion layer, which is dependent on charge carriers.Doping enhances the depletion layer because a larger diffusion current leads to more ions on each side of the depletion layer.

(c) Full Wave Rectifier :

The circuit diagram for full wave rectifier using two junction diodes is shown in figure.

A simple full way rectifier consists of two transformers mutually inducted and two diodes which filter the negative cycle of alternating current. At any instant the voltage at A(input voltage of diode 1) and end B (input voltage of diode 2) of the secondary with respect to the centre tap will be out of phase. Suppose during a positive half cycle of Ac input, the end A is positive and end B is negative with respect to the centre tap. Then diode 1 gets forward biased(allows the flow of current) and diode 2 gets reversed biased(does not allow the flow of current). Hence, the current flows through the diode 1 towards the centre tap along the path AXY as shown in the above diagram. Similarly, during the negative half cycle of Ac input the end B becomes positive and end A becomes negative. Hence, diode 1 gets reversed biased and diode 2 gets forward biased resulting in the current to flow from diode 2 to the centre tap along the path BXY as shown in the above diagram. As during both the half cycles the input a.c. the current through the load resistor will flow from X to Y and will keep on pulsating. Given below is the waveform for the full wave rectifier indicating inputs of AC and the output voltage.

Define the term 'depletion layer' and 'barrier potential' for a $P - N$ junction diode. How does an increase in doping concentration affects the width of the depletion region? Draw the circuit of a full-wave rectifier. Explain it's working.

Important Questions on Electronic Devices

Learn and Prepare for any exam you want !

Define the term 'depletion layer' and 'barrier potential' for a P-N junction diode. How does an increase in doping concentration affects the width of the depletion region? Draw the circuit of a full-wave rectifier. Explain it's working.

Important Questions on Electronic Devices

Learn and Prepare for any exam you want !

Define the term 'depletion layer' and 'barrier potential' for a $P - N$ junction diode. How does an increase in doping concentration affects the width of the depletion region? Draw the circuit of a full-wave rectifier. Explain it's working.