Page 122 - MATLAB an introduction with applications

Electrical Circuits ——— 107

fprintf (‘The curent in the circuit is %f amp’,i)
fprintf(‘\nThe total power dissipated in the circuit is %f watts\n’,ptotal)
MATLAB Output:
Enter the source voltage
Enter values of resistors as elements in a row vector
[10 7 6 9 4 7.5 5]
Resistance Voltage Power
(ohm) (volt) (watt)
10.0000 2.4742 14.8454
7.0000 1.7320 10.3918
6.0000 1.4845 8.9072
9.0000 2.2268 13.3608
4.0000 0.9897 5.9381
7.5000 1.8557 11.1340
5.0000 1.2371 7.4227

The current in the circuit is 0.247423 amp.
The total power dissipated in the circuit is 2.969072 watt.

Example E2.3: Figure E2.3 shows a semiconductor diode and the current flowing through the diode is
given by:

 qv d 
i D = i 0 [exp   kT   − 1 ]

where v d = the voltage across the diode (volt)
i 0 = the leakeage current of the diode (amp)
k = Boltzmann’s constant (1.38 ×10 –23 joule/K)
q = the charge of an electorn (1.6 × 10 –19 coulombs)
T = temperature (in K)
i D = the current flow through the diode (amp)
(a) Write a MATLAB program to calculate the current flowing through this diode for all
voltages from –0.2 V to + 0.25 V in 0.01 V steps.
o
o
o
(b) Repeat the procedure in (a) for 70 F, 200 F and 400 F.
(c) Plot the current as a function of applied voltage.

F:\Final Book\Sanjay\IIIrd Printout\Dt. 10-03-09