PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

146 Practical MATLAB® Applications for Engineers

>> W1BTU=W1J/1055, W2BTU=W2J/1055

W1 _ BTU =

0.0474

W2 _ BTU =

0.0152

>> W1 _ ftlbf =W1J*0.737,W2 _ ft1bf=W2J*0.737

W1 _ ft1bf =

36.8500

W2 _ ft1bf =

11.7920

>> W1 _ Kwh=W1J/3.6*10^-6, W2 _ Kwh=W2J/3.6*10^-6

W1 _ Kwh =

1.3889e-005

W2 _ Kwh =

4.4444e-006

Example 2.6

Create the script fi le linearity that verifi es the linear relation between the current

and voltage in a resistive circuit (Ohm’s law), and the nonlinearity of its power for

the circuit shown in Figure 2.43, where the applied voltage V 0 varies over the range

10 V ≤ V 0 ≤ 1000 V in linear increments of 10 V by obtaining the following plots:

1. V 0 versus I


2. V 0 versus PR (power dissipated by R = 1 kΩ)

FIGURE 2.43

Network of Example 2.6.

1 kΩ

V 0

l

−

+

MATLAB Solution

%Script file: linearity

R=1.0e3;

V=10:10:1000;

I=V./R;

P=I.*V;

subplot(2,1,1)

plot (V,I*1000)

title(‘Current vs. Voltage’)

xlabel(‘Voltage (Volts)’)

ylabel(‘Current (mA)’)

subplot(2,1,2)

plot (V,P)

title(‘Power vs. Voltage’)

xlabel(‘Voltage (Volts)’)

ylabel(‘Power (watts)’)

The script fi le linearity is executed and the results are shown in Figure 2.44.