Chapter 7 : Display Devices and recorders

Example 7.1 Page No : 349

In [1]:
# Variables
N  =  4.;

# Calculations and Results
R = 1./10**N;
print "Resolution of the meter = ", R
VR = 1;
R1 = VR*R;
print "Resolution of the meter for voltage range 1V = ", R1
VR1 = 10;
R2 = VR1*R;
print "Resolution of the meter for voltage range 10V = ", R2

Resolution of the meter =  0.0001
Resolution of the meter for voltage range 1V =  0.0001
Resolution of the meter for voltage range 10V =  0.001

Example 7.2 Page No : 351

In [2]:
# Variables
N  =  3.;

# Calculations and Results
R = 1./10**N;
print "Resolution of the meter = ", R
print "12.98 will be layed as 12.980 on 10V scale"
VR = 1.;
R1 = VR*R;
print "Resolution of the meter for voltage range 1V = ", R1
print "0.6973 will be layed as 0.6973 on 1V scale"
VR1 = 10;
R2 = VR1*R;
print "Resolution of the meter for voltage range 10V = ", R2
print "0.6973 will be layed as 00.697 on 10V scale"

Resolution of the meter =  0.001
12.98 will be layed as 12.980 on 10V scale
Resolution of the meter for voltage range 1V =  0.001
0.6973 will be layed as 0.6973 on 1V scale
Resolution of the meter for voltage range 10V =  0.01
0.6973 will be layed as 00.697 on 10V scale

Example 7.3 Page No : 353

In [3]:
# Variables
R = 5.;

# Calculations and Results
V = 0.005*R;
print "0.5 percent of the reading", V
TPE = V+0.01;
print "Total possible error (V) = ", TPE
R1 = 0.10;
V1 = 0.005*R1;
TPE1 = V1+0.01;
print "Total possible error (V) = ", TPE1
PE = (TPE1/0.1)*100;
print "Percentage error = ", PE

0.5 percent of the reading 0.025
Total possible error (V) =  0.035
Total possible error (V) =  0.0105
Percentage error =  10.5

Example 7.4 Page No : 355

In [4]:
# Variables
N = 034;
t = 10.*10**-3;

# Calculations
f = N/t;

# Results
print "frequency(Hz) = ", f

frequency(Hz) =  2800.0

Example 7.5 Page No : 357

In [5]:
# Variables
R = 5*10**6;

# Calculations and Results
V = 0.00005*R;
print "0.005 percent of the reading(micro sec) = ", V
LSD = 1;
ME = V+1;
print "Maximum error (micro sec) = ", ME
R = 500;
V = 0.00005*R;
print "0.005 percent of the reading(sec) = ", V
LSD = 1;
ME = V+1;
print "Maximum error (sec) = ", ME

0.005 percent of the reading(micro sec) =  250.0
Maximum error (micro sec) =  251.0
0.005 percent of the reading(sec) =  0.025
Maximum error (sec) =  1.025

Example 7.6 Page No : 359

In [8]:
import math

# Variables
D = 8.*10**-3;

# Calculations and Results
A = D**2;
print "A = ", A
J = 8*10**-3;
K = 16*10**-3;
B = 4*J*K;
print "B = ", B
print "since A<B so the instrument is underdanped",
th = (100*math.pi)/180;
i = 10*10**-3;
F = 0.2*10**-6;
G = (K*th+F)/i;
l = 65*10**-3;
d = 25*10**-3;
N = G/(B*l*d);
print "number of turns = ", N
i = F/G;
print "current required to overcome friction (A)", i

 A =  6.4e-05
B =  0.000512
since A<B so the instrument is underdanped number of turns =  3356426.44614
current required to overcome friction (A) 7.16192114565e-08

Example 7.7 Page No : 361

In [9]:
# Variables
Lam = 2.5*6.25;
f = 50000;

# Calculations
S = Lam*10**-6*f;

# Results
print "speed(m/s) = ", S

speed(m/s) =  0.78125

Example 7.8 Page No : 363

In [10]:
# Calculations
ND = 12000/1.5;

# Results
print "Number density (numbers/mm)", ND

Number density (numbers/mm) 8000.0

Example 7.9 Page No : 365

In [11]:
# Variables
Y1 = 1.25;
Y2 = 2.5;

# Calculations
PA = math.asin(Y1/Y2);

# Results
print "phase angle (degree)", PA
print "possible angle are 30 degree and 330 degree",

phase angle (degree) 0.523598775598
possible angle are 30 degree and 330 degree

Example 7.10 Page No : 367

In [12]:
import math

# Calculations and Results
print "if spot generating pattern moves in the clockwise direction"
Y1 = 0;
Y2 = 5;
PA = math.asin(Y1/Y2);
print "phase angle (degree)", PA
Y1 = 2.5;
Y2 = 5;
PA = math.asin(Y1/Y2);
print "phase angle (degree)", PA
Y1 = 3.5;
Y2 = 5;
PA = math.asin(Y1/Y2);
print "phase angle (degree)", PA
Y1 = 2.5;
Y2 = 5;
PA = 180-(math.asin(Y1/Y2));
print "phase angle (degree)", PA

if spot generating pattern moves in the clockwise direction
phase angle (degree) 0.0
phase angle (degree) 0.523598775598
phase angle (degree) 0.775397496611
phase angle (degree) 179.476401224