Hai everyone I am e back to tell the story of myself.....
After the formation of a barrier i.e... The PN junction the electrons and holes began to search for ways to contact their friends. Though there was a large attraction between the still free electrons and holes the aftereffects of meeting,i.e..the potential barrier prevented them from meeting. Thus began the search for new ways of meeting........
The application of pressure from p and n sides due to pushing of our friends for more space as happens in population explosion like the pressure in the region of war-zone during the diplomatic war status between the two countries like the increase in demand and prices of goods due to blocking of trade route by ottoman Turks leads to the thinning of PN junction just as the area near the border decreases due to employment of more soldiers in the border areas.
Similarly due to deposition of more electrons on N-side of the PN junction due to the sending of electrons from negative terminal of the battery. Similarly at p side the battery extracts all the electrons present in the region leaving behind a large concentration of positive ions or holes which also pushes the holes towards the barrier. This is the state of forward bias. As we gain energy from the battery we prepare to end this border rule i.e.we move towards the barrier in full force and hit it simultaneously. When we have sufficient energy the threshold breaks just like intervention of UNO during a war, just like the angry retort of hungry people. The current flow occurs in the following sequence..
After the formation of a barrier i.e... The PN junction the electrons and holes began to search for ways to contact their friends. Though there was a large attraction between the still free electrons and holes the aftereffects of meeting,i.e..the potential barrier prevented them from meeting. Thus began the search for new ways of meeting........
The application of pressure from p and n sides due to pushing of our friends for more space as happens in population explosion like the pressure in the region of war-zone during the diplomatic war status between the two countries like the increase in demand and prices of goods due to blocking of trade route by ottoman Turks leads to the thinning of PN junction just as the area near the border decreases due to employment of more soldiers in the border areas.
Similarly due to deposition of more electrons on N-side of the PN junction due to the sending of electrons from negative terminal of the battery. Similarly at p side the battery extracts all the electrons present in the region leaving behind a large concentration of positive ions or holes which also pushes the holes towards the barrier. This is the state of forward bias. As we gain energy from the battery we prepare to end this border rule i.e.we move towards the barrier in full force and hit it simultaneously. When we have sufficient energy the threshold breaks just like intervention of UNO during a war, just like the angry retort of hungry people. The current flow occurs in the following sequence..
- The flow of electrons from the battery.
- The flow of electrons in conduction band in n-region.
- Recombination of electrons and holes at the junction and conversion into valence electrons with release of energy.
- Travelling of electrons as valence electrons in p-region.
- Finally,move as conduction electrons into p side of battery.
Since during this process, due to flow of electrons as conduction in n region and then recombines and move as valance electrons and similarly through p region to the battery, resistance offered to flow of electrons is very very low.
Thus the barrier is broken for now until another person attacks and occupies (until power from battery is present)…………………………….
On the other hand if there is a pull of majority charge carriers in each of the sides, the barrier width increases, just like the gap between two persons increases with mutual hatred. In this case the battery does the work of pulling away the current carriers from the junction. Due to pull of electrons from positive side of battery and push of electrons from negative side, the junction gap increases and blocks the flow of current, this implies that the resistance of the PN junction increases. This is called reverse bias of a diode………….
But my counterparts (holes) who were stuck on N side and electrons blocked on P side though are in very less numbers can easily pass through the barrier as the paid customers of ottoman Turks or the monks who take no care about war. That is for minority carriers (the non-doped thermally produced electron hole pairs) the barrier does not matter. For this current the reverse bias acts as forward bias itself. This current is independent of external forces (other than temperature) just as monks are detached from worldly pleasures. This reverse current increases as temperature increases.
Thus diode or PN junction acts as a one way electronic component which provides many uses….
In my next story let us know about my changes in the junction due to temperature and others and wonders we perform inside the junction…………
