in this post we will discuss about Hall Effect , this topic is very important for many competitive exams. if you have any doubt regarding this post then comment below, for video lectures on electronics devices and circuit subscribe our you tube channel, all links given below.

Hall effect

here are the important points for which hall effect is used

•  To find the type of semiconductor specimen whether semiconductor is P-type or N-type
•  To find the charge concentration
•  To find the mobility of charge carrier

What is Hall Effect

Whenever a current carrying semiconductor is subjected to a magnetic field, there will be an induced electric field in the perpendicular direction of the plane consist of I & B, which intern exert a force over the carrier is known ass hall effect.

In above shown figure the direction of current is considers towards X-direction and direction of magnetic field is in Z-direction so induced electric field will have Y-direction because of Lorentz force  

working

we can easily find the types of semiconductor specimen whether it is P-type or N-type by hall effect. if the consider specimen is N-type then electron will be accumulated to the lower surface of the bar which makes hall voltage \({ V }_{ H }\) positive, similarly if the consider specimen is P-type then holes will be accumulated to the lower surface of the semiconductor bar which makes hall voltage \({ V }_{ H }\) negative.

NOTE – in any case (either P-type or N-type) the direction of exerted force over the charge carrier is negative Y-direction.

 Hall Voltage

\({ V }_{ H }\quad =\quad \frac { BI }{ \rho W } \)    —————(1)

Hall coefficient 

It is defined as the reciprocal of charge density (ρ)

\({ R }_{ H }\quad =\quad \frac { 1 }{ \rho } \)

by equation (1)

\({ R }_{ H }\quad =\quad \frac { W.{ V }_{ H } }{ BI } \)

Application of Hall Effect

•  To determine type of extrinsic semiconductor (using polarity of \({ V }_{ H }\))
•  To determine carrier concentration (n)
•  Used in magnetic field meter
•  As a hall effect multiplier
•  To calculate mobility

NOTE – Hall effect is very less effective in case of metal because in metal n is very large

\({ V }_{ H }\) will be very small in order of micro volts.

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