i-v curves of common emitter bjt in matlab

To plot the current-voltage (I-V) curves of a common emitter Bipolar Junction Transistor (BJT) in MATLAB, you can follow these steps:

1. Define the parameters of the BJT (such as alpha, Vbe, Is) and the circuit components (such as resistors).
2. Write the KVL and KCL equations for the circuit.
3. Use MATLAB's symbolic math toolbox to solve the equations and obtain the transistor characteristics.
4. Plot the I-V curves.

Here is an example MATLAB code snippet to plot the I-V curves of a common emitter BJT:

main.m
% BJT parameters
Is = 1e-15;  % Saturation current (A)
Vt = 25e-3;  % Thermal voltage (V)
alpha = 0.98;  % Common emitter current gain

% Define range of V_BE (base-emitter voltage)
V_BE = linspace(0.5, 0.8, 100);  % Vary V_BE from 0.5V to 0.8V

% Calculate collector current I_C
I_C = Is * (exp(V_BE/Vt) - 1);

% Plot I-V curve
figure;
plot(V_BE, I_C, 'b', 'LineWidth', 2);
xlabel('Base-Emitter Voltage V_{BE} (V)');
ylabel('Collector Current I_{C} (A)');
title('Common Emitter BJT I-V Characteristic');
grid on;
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This code snippet defines the BJT parameters, calculates the collector current for varying base-emitter voltage, and plots the I-V curve.

You can run this script in MATLAB to visualize the common emitter BJT I-V characteristics.