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A pn At the junction, the diode electrons move from the N side to the P side and the holes move from the P side to the N side. This form is transmitted to the pn junction diode. And this leads to scarcity zones. The inhibitory potential is formed in the PN junction diode by the presence of an emmonial charge.
In a forward diode, the holes move from the P side to the other side due to repulsion from the positive terminal of the external battery. And electrons move from n side to p due to repulsion from the negative terminal of the external battery. Therefore the hole current through the p-field is the hole drift current and the electron electron current through the n field is current. When the holes reach the junction they travel from the N side due to the concentration gradient. This leads to hole propagation current through the N side. And when the electrons arrive at the junction they pass through the p region due to the concentration gradient. This electron diffusion current leads to p. So the total current is some of all the drift and propagation currents of electrons and holes.
The entire current current is greater than the diffusion current and the electron drone current is higher than the electron diffusion current. Therefore the hole region is maximum at the far end of the p-region and the electron flow is more at the far end of the n-region. And the hole current decreases when moving towards the n-region and the electron current decreases when moving towards the p-region.
Total current = hole drift current + hole propagation current + electron drift current + electron diffusion current
Although the electron diffusion and stream of drift at each point in the field and the diffusion of holes and the flow of drift vary, the total amount of current at the junction remains constant at all times.
Total current in p-region = hole drift current + electron diffusion current
Total current in the N-region = electron drift current + hole propagation current
Total current at the junction = Total current in the P-region + Total current in the N-region
Effect of temperature on diode
The diode is a temperature dependence device. Because reverse saturation current and diode voltage are temperature dependent.
Reverse bias currently due to minority fee carriers. The minority charge carrier increases when the temperature increases. Thus the reverse saturation current also increases. But the diode voltage decreases as the temperature increases. So the reverse current is directly proportional to the temperature and the voltage is inversely proportional to the temperature.
A diode has two types of capacitance.
1.Transmission capacitance / depletion current
2. Sag capacitance
It appears when the diode is in reverse bias. The subtraction width increases when a reverse voltage is increased. So the amount of Immobile Charge Carrier increases. The rate of change of the immobile charge carrier with respect to the reverse voltage is called the transition potential. When a diode is used as a voltage dependent capacitor it is called a varactor diode or varicap or volt cap. A normal junction that is a sudden junction is not considered as a vectors. Therefore a special diode, known as a sudden diode, is used as a vectors diode. Varactor diode always operates under reverse bias conditions.
It appears when the diode is in forward bias. Hence consider the pn junction in forward bias. When a forward bias is applied the hole is injected into the N-side and the hole is injected into the P-side. Therefore the positive charge carried by the pores through the N-side and the negative charge carried by electrons in the P-side is known as the injection charge. The charge also increases when the applied forward voltage increases as a greater number of charges cross the junction. The rate of charge in relation to the forward voltage applied is called the propagation capacitance.