Chapter 17: Voltage Regulators

Example 17.1, Page Number:552

In [1]:
%matplotlib inline

Welcome to pylab, a matplotlib-based Python environment [backend: module://IPython.zmq.pylab.backend_inline].
For more information, type 'help(pylab)'.
In [2]:
#variable declaration
Del_V_out=0.25;
V_out=15;
Del_V_in=5;    #All voltages in Volts

#Calculations
line_regulation=((Del_V_out/V_out)/Del_V_in)*100;

#Result
print('line regulation in %%V is %f' %line_regulation)

line regulation in %V is 0.333333

Example 17.2, Page Number: 553

In [3]:
# Variable Declaration
V_NL=12.0;    #No load output voltage in Volts
V_FL=11.9;  #Full load output voltage in Volts
I_F=10.0;     #Full load current in milli-Amperes

#Calculations
load_regulation=((V_NL-V_FL)/V_FL)*100;
load_reg=load_regulation/I_F;

#Result
print('load regulation as percentage change from no load to full load = %f'%load_regulation)
print('\nload regulation as percentage change per milliampere = %f' %load_reg)

load regulation as percentage change from no load to full load = 0.840336

load regulation as percentage change per milliampere = 0.084034

Example 17.3, Page Number: 556

In [4]:
V_REF=5.1    #Zener voltage in volts
R2=10*10**3;
R3=10*10**3; #resistances in ohm
V_out=(1+(R2/R3))*V_REF;
print('output voltage in volts = %.1f'%V_out)

output voltage in volts = 10.2

Example 17.4, Page Number: 557

In [5]:
R4=1;    #Resistance in Ohms
I_L_max=0.7/R4;
print('maximum current provided to load(in amperes) = %.1f'%I_L_max)

maximum current provided to load(in amperes) = 0.7

Example 17.5, Page Number: 560

In [6]:
V_IN=12.5;    #maximum input voltage in volts
R1=22;    #In Ohms

V_OUT=0;
V_R1=V_IN-V_OUT;   #Voltage across R1
P_R1=(V_R1*V_R1)/R1;    #maximum power dissipated by R1
print('maximum power dissipated by R1 in WATTS = %f'%P_R1)

maximum power dissipated by R1 in WATTS = 7.102273

Example 17.6, Page Number: 569

In [7]:
print('SAME AS EX-2.8 in CHAPTER-2')

SAME AS EX-2.8 in CHAPTER-2

Example 17.7, Page Number: 572

In [8]:
I_max=700*10**-3;    #in Amperes
R_ext=0.7/I_max;
print('value of resistor in Ohms for which max current is 700mA = %f'%R_ext)

value of resistor in Ohms for which max current is 700mA = 1.000000

Example 17.8, Page Number: 572

In [9]:
V_OUT=24.0;    #Output voltage in Volts
R_L=10.0;    #Load resistance in Ohms
V_IN=30.0;    #Input voltage in Volts
I_max=700.0*10**-3;   #maximum interal current in Amperes
I_L=V_OUT/R_L;    #load current in amperes
I_ext=I_L-I_max;    #current through the external pass transistor in Amperes
P_ext_Qext=I_ext*(V_IN-V_OUT);    #power dissipated
print('power dissiated(in WATTS) by the external pass transistor = %.1f'%P_ext_Qext)
print('\nFor safety purpose, we choose a power transistor with rating more than this, say 15W')

power dissiated(in WATTS) by the external pass transistor = 10.2

For safety purpose, we choose a power transistor with rating more than this, say 15W

Example 17.9, Page Number: 574

In [10]:
V_out=5.0;    #7805 gives output voltage of 5V
I_L=1.0;    #constant current of 1A
R1=V_out/I_L;
print('The value of current-setting resistor in ohms = %d'%R1)

The value of current-setting resistor in ohms = 5