Determine the voltage across the inductor in an RL circuit:
Let us compute the voltage across the inductor for t≥0 using the following expression:
${{v}_{L}}(t)=-R{{I}_{lo}}{{e}^{-t/\tau }}u(t)$
Whereas the inductor initial current is 1mA and time constant τ=L/R=5ms.
- You May Also Read: Series RL Circuit Analysis Theory
It’s time to write some code in Matlab to calculate the inductor voltage:
%RL Circuit Analysis
clear all;close all;clc
%%Circuit Parameters
R= 20; % Resistance (20 Ohm)
L= 100e-3; % Inductance (100mH)
tau=L/R; % RL Time Constant
I_lo=1e-3; % Inductor Initial Current
Time=0:tau/100:5*tau; % Sampling Time
V_L=-R*I_lo.*exp(-Time./tau).*heaviside(Time);
plot(Time,V_L)
xlabel('Time (s)')
ylabel('Amplitude (V)')
title('V_L')
axis([0 5*tau -21e-3 0]) % Manual Axis Limits adjustment
%=============================================
Results:
