Electronic Devices: Drift current

[@nikolapantelic9443]

This was absolutely the most detailed and on point video for drift current, thanks.

[@MahmutEbrarACIKVEVO]

At 4:10, there is a dog barking in the background. I dunno why I said this.

[@shivamkumarsingh6393]

We love You 3000!!!

[@wanderingdna]

THANK YOU SO MUCH SIR. GOD BLESS U.

[@gamesstation2035]

U the best explainer person I hear to this time

[@joannawakaka3038]

i heard barking @4:00

[@mz3282]

Very good for revision! Thanks

[@lakshmananb158]

very useful to listen ur class than studied in books

[@6s6]

I love you so much. Thank you so much.

[@kameeltv9126]

please why hole of mass is heavier than electrons?

[@iamisro6636]

ks barau Well not hole of mass but mass of holes . 😉

[@iamisro6636]

next , you are talking about effective mass term , which is not true always to be more for holes than electrons . In many cases effective mass of electrons is more than the holes , this depends on the type of material . In simple effective mass of electron is considered as mass of electron when revolving.

[@iamisro6636]

ks barau : The concept of effective mass follows from physicists' love for simple relations such as Ohm's law (current density = conductivity x electric field intensity) or Newton's second law of motion (acceleration = force / mass). For a free electron, the mass in the latter is just the electron mass. But, if one wants to write a similar relation for a charge carrier in a crystal lattice, the situation changes. Going through the math (see any solid state physics textbook) allows you to write F = m x a, where the force is charge x electric field, but the mass is no longer the mass of the electron, but reflects the curvature of the conduction band bottom (for electrons) or valence band top (for holes), as it is inversely proportional to the second derivative of the energy as a function of k. This is the so-called effective mass. Again, physicists like simple things, so one often expresses the effective mass as a constant x electron mass, although this has very little (or nothing) to do with the actual physics of the situation. Hence: it is just a practical mathematical construction aimed at simplifying equations (in a similar manner as the reciprocal lattice, for example). The hole itself is also a mathematical construction helping us to avoid using negative values for mass in the simple equations (the effective mass for conduction occurring through the unoccupied electron states in the valence band would be negative, if we didn't invert the charge). In the majority of cases, the top of the valence band is clearly "flatter" than the bottom of the conduction band. From this follows that the hole effective mass is often larger than the electron effective mass. The top of the valence band tends to be flatter due to the asymmetry of the situation: you are talking about the highest occupied states for electrons. The bottom of the conduction band is formed by the lowest unoccupied states.

[@anuragmittal9816]

very good

[@IamHewage]

thank you!

[@studywithambikasingh8040]

thanks sir

[@unfilteredlife6272]

1000 likes

[@studywithambikasingh8040]

please make video on carier transport in silicon in hindi sir please

[@iamisro6636]

usha kumari 😂😂😂😂😂😂😂 why dont you leave engineering and try art .

[@muhammadazzrul2342]

hai i m from malaysia class dr sensei

[@affihmad7697]

hi classmate