One concept at a time per video -- this is a good teaching technique which you seldom see elsewhere. I'm not a student, nor an expert, but I love these videos, which I just watch out of interest. Thank you Mahesh!
The first diodes were vacuum tubes. The cathode was heated up so that it "evaporated" elecrons, and the anode would collect electrons only if it was at a potential higher than the cathode. And there were vacuum tube triodes as well, which were used to amplify. I am old enough to remember taking vacuum tubes from a television to a store to test which one burned out.
*Why Diode* ? At 7:00 - A node in any circuit that is directional in nature since it conducts only in 1 direction is called Directional Node or *DIODE* .
Sir please clear my doubt. When forward biased, the depletion region voltage 0.7 is opposed by the applied voltage. But when the applied voltage is less than the cut off voltage, the current should be zero. Only when the applied voltage overcome the cut off voltage current should flow through the circuit. Until that no current should flow through the circuit. That is, when forward biased, the depletion layer becomes narrow.But it still exist.So some more electrons and holes enter the depletion layer and recombine. But eventually the current due to majority charge carriers should be balanced by the minority charge carriers moving in the opposite direction.So equilibrium should be reached once again and no net current should flow through the circuit.
Without any applied voltage, the two currents (drift and diffusion) cancel out, giving net current zero. So when you forward bias, however small the voltage be, the depletion region shortens, and diffusion increases. The equilibrium is now lost, and a net current flows. Also note, the recombination of the majority carriers IS responsible for the diffusion current. It's the recombination that maintains the concentration gradient required for diffusion current. [If this sounds confusing, there is a video on '' explaining it in great detail]. Happy to answer more questions.
Sir please clear my doubt, in our book it is written that as we increase the reverse bias current is going to be increased as minority carriers attain high velocity and knock down the bound electrons from covalent bonds and the current increases. How is this possible and is this even right?
Electrostatics and circuits belong to one science not two. For a unified approach to learning Current and the process of conduction watch these two videos i. ua-cam.com/video/REsWdd76qxc/v-deo.html and ii. ua-cam.com/video/8BQM_xw2Rfo/v-deo.html Also, in the textbooks referred in the last frame of video i you will find descriptions of the operation of resistors, capacitors and inductors using this approach which makes it easier to understand. There are also chapters in the textbook references which explain the operation of diodes and transistors using the unified approach. Provided also are accurate descriptions of cut-in voltage of p-n junction diodes.
The semiconductor series is really awesome Mr.Mahesh, you really deserve your current post of Khan academy India science lead!
6:35 Diode comes from the greek word "δίοδος"
δι (two) is a prefix and οδός (ode) means road
Amazing video! We need more videos on Khan Academy India!
Such an amazing video!!!
One concept at a time per video -- this is a good teaching technique which you seldom see elsewhere. I'm not a student, nor an expert, but I love these videos, which I just watch out of interest. Thank you Mahesh!
Beautifully explained in depth ❤❤..that too in a structured manner..has made the chapter crystal clear to me😊😊
wow u have explained everything so nicely every graph every point of ncert
You are trully a bleesing for physics students.keep up the good work!
The first diodes were vacuum tubes. The cathode was heated up so that it "evaporated" elecrons, and the anode would collect electrons only if it was at a potential higher than the cathode. And there were vacuum tube triodes as well, which were used to amplify. I am old enough to remember taking vacuum tubes from a television to a store to test which one burned out.
*Why Diode* ?
At 7:00 - A node in any circuit that is directional in nature since it conducts only in 1 direction is called Directional Node or *DIODE* .
love you sir that's it.
Finally understood this chapter after so long!
1:44 Sir ,is the cut in voltage at forward biasing is equal to the barrier potential of the semiconductor?
Ig so
Great explanation....thank u so much for such an explanation 🙏🙏🙏
Mind blowing lectures
Sir please clear my doubt.
When forward biased, the depletion region voltage 0.7 is opposed by the applied voltage. But when the applied voltage is less than the cut off voltage, the current should be zero. Only when the applied voltage overcome the cut off voltage current should flow through the circuit. Until that no current should flow through the circuit.
That is, when forward biased, the depletion layer becomes narrow.But it still exist.So some more electrons and holes enter the depletion layer and recombine. But eventually the current due to majority charge carriers should be balanced by the minority charge carriers moving in the opposite direction.So equilibrium should be reached once again and no net current should flow through the circuit.
Without any applied voltage, the two currents (drift and diffusion) cancel out, giving net current zero. So when you forward bias, however small the voltage be, the depletion region shortens, and diffusion increases. The equilibrium is now lost, and a net current flows.
Also note, the recombination of the majority carriers IS responsible for the diffusion current. It's the recombination that maintains the concentration gradient required for diffusion current. [If this sounds confusing, there is a video on '' explaining it in great detail]. Happy to answer more questions.
Sir please clear my doubt, in our book it is written that as we increase the reverse bias current is going to be increased as minority carriers attain high velocity and knock down the bound electrons from covalent bonds and the current increases. How is this possible and is this even right?
Awesome
Superb.....
It is actually path. It comes from the greek word Δίοδος which means 2 and road-path.
Great video thanks!
name of the app?
Thank you
Di means 2 and ode means the two symbols represent (+) which is anode(ode) and (-) which is cathode(ode)
dope
sir plzzz can you make a video on a photo diode
👍👍👍
🙏🙏🙏🙏
depletion layer don’t disappear. 1:24
Electrostatics and circuits belong to one science not two. For a unified approach to learning Current and the process of conduction watch these two videos i. ua-cam.com/video/REsWdd76qxc/v-deo.html and
ii. ua-cam.com/video/8BQM_xw2Rfo/v-deo.html
Also, in the textbooks referred in the last frame of video i you will find descriptions of the operation of resistors, capacitors and inductors using this approach which makes it easier to understand.
There are also chapters in the textbook references which explain the operation of diodes and transistors using the unified approach. Provided also are accurate descriptions of cut-in voltage of p-n junction diodes.