To determine value of Boltzmann's constant by studying forward characteristic.

Boltzmann constant gives relationship between the temperature T of the particle and the equivalent thermal energy.
E = Thermal Energy of a particle = kT
Theoretical value of Boltzmann Constant ( k ) =1.38 x 10^-23 J/K.
At room Temperature,
T=300K,
E = 0.02586 eV

Role of Boltzmann's Constant in Forward Biasing of Semiconductor Diode.

Forward Biasing is done by providing positive potential to p side of P-N Junction diode. This reduces the existing depletion layer and electron can easily travel through the depletion layer. Since minority carriers are not given by external power source and amount of majority carriers is higher than minority carriers in case of Forward Biasing.
The current due to forward Biasing also depends on Temperature of system. As Temperature varies ,energy of electron also changes. Hence the role of Boltzmann Constant is vital in relation of Saturation current and Voltage.

This shows characteristic between Current and Voltage different than one formed due to Ohm's Law but with:-

I=I_s(e^qV/nkT-1)
where n=1 for Germanium Diode
n=2 for Silicon Diode.

The above equation is in form of straight line in form of y = mx+c



Forward characteristic for Silicon Diode can be plotted on graph using Voltage and Current values

1. Make the connections as shown in the figure with p-n diode in the forward bias mode.
2. Slowly increase the input voltage from zero in convenient steps, and note the voltage V across the diode and the current I through it. Take readings till the current is about 20mA. To get a large number of readings voltmeter and milliammeter should be of low least counts. A digital multimeter can be used for the purpose.
3. Plot the graph between V along x-axis and log10 i along y-axis.

Animation of the experiment:--

Temperature T= ...° K

S.No.	Voltage, V (volts)	Current (mA)	Current I, (in Amphere)	log10 I
1
2
3
4

Calculation

The experimentally obtained value of Boltzmann's constant = ...JK^-1
Standard value = ... 1.38 * 10^-23 JK^-1
% Error = ...%

1. Ensure that p-side is made positive w.r.t the n-side.
2. Increase the supply voltage slowly from zero. Take care that input voltage does not increase excessively; the safe value for BY 127 is about 2V. Otherwise, the diode current will be harmfully large.
3. The temperature T should be noted down in Kelvin.
4. It should be remembered that n=1 for Germanium diode and 2 for Silicon diode.

1. Boltzmann's constant (Byju's)
2. Boltzmann's constant (wikipedia)