Chapter 15 , Cathode Ray Oscilloscope

Example 15.1 , Page Number 537

In [15]:
#Variables

l = 25.0 * 10**-3                #Length of plates (in meter)
d = 5.0 * 10**-3                 #Distance between plates (in meter)
S = 0.20                         #Distance between screen and centre of plates (in meter) 
Va = 3000.0                      #Accelerating voltage (in volts)
tracelen = 0.1                   #Trace length (in meter)
y = tracelen/2                   #vertical distance (in meter)

#Calculation

Vd = 2*d*Va*y/(l*S)              #Deflecting voltage (in volts)
Vrms = Vd/2**0.5                 #RMS value of voltage (in volts)
defsen = l*S/(2*d*Va)            #Deflection sensitivity (in meter per volt)

#Result

print "Deflection sensitivity : ",round(defsen * 10**3,3),"mm/V."

Deflection sensitivity :  0.167 mm/V.

Example 15.2 , Page Number 537

In [14]:
#Variables

Va = 1000.0                       #Accelerating voltage (in volts)
e = 1.6 * 10**-19                 #Charge on electron (in Coulomb)
m = 9.1 * 10**-31                 #Mass of electron (in kilogram) 

#Calculation

v = (2*Va*e/m)**0.5               #Maximum velocity of electrons (in meter per second) 

#Result

print "Maximum velocity of electrons : ",round(v*10**-6,2),"e+6 m/s."

Maximum velocity of electrons :  18.75 e+6 m/s.

Example 15.3 , Page Number 538

In [11]:
#Variables

defsen = 0.05 * 10**-3           #Deflection Sensitivity (in meter per volt)
spotdef = 5.0 * 10**-3           #Deflection factor (in volt per meter)

#Calculation

V = spotdef/defsen               #Applied voltage (in volts)

#Result

print "Applied voltage : ",V,"V."

Applied voltage :  100.0 V.

Example 15.4 , Page Number 538

In [10]:
#Variables

l = 20.0 * 10**-3                #Length of plates (in meter)
d = 5.0 * 10**-3                 #Distance between plates (in meter)
S = 0.25                         #Distance between screen and centre of plates (in meter) 
Va = 3000.0                      #Accelerating voltage (in volts)     

#Calculation

defsen = l*S/(2*d*Va)            #Deflection Sensitivity (in meter per volt)
deffact = 1/defsen               #Deflection factor (in volt per meter)

#Result

print "Deflection sensitivity : ",round(defsen*10**3,4),"mm/V."
print "Deflection factor : ",deffact*10**-3,"V/mm."

Deflection sensitivity :  0.1667 mm/V.
Deflection factor :  6.0 V/mm.

Example 15.6 , Page Number 549

In [6]:
#Variables

tangv = 3.0                      #Positive of Y - peak to vertical line
tangh = 2.0                      #Positive of X - peak to horizontal line 

#Calculation

ratio = tangv/tangh              #Ratio of freq. of vertical and horizontal signals 

#Result

print "Ratio of freqency of vertical and horizontal signals : ",ratio,"."

Ratio of freqency of vertical and horizontal signals :  1.5 .

Example 15.7 , Page Number 549

In [5]:
#Variables

fx = 3.0 * 10**3                 #Frequency of horizontal input (in Hertz)
tangv = 2.5                      #Positive of Y - peak to vertical line
tangh = 1.0                      #Positive of X - peak to horizontal line 

#Calculation

fy = fx*tangv/tangh              #Frequency of vertical input (in Hertz)

#Result

print "Frequency of vertical input : ",fy,"Hz."

Frequency of vertical input :  7500.0 Hz.

Example 15.8 , Page Number 549

In [3]:
#Variables

fx = 1000.0                      #Frequency of horizontal input (in Hertz)
tangv = 2.0                      #Points of tangency to vertical line
tangh = 5.0                      #Points of tangency to horizontal line 

#Calculation

fy = fx*tangh/tangv              #Frequency of vertical input (in Hertz)

#Result

print "Frequency of vertical input : ",fy,"Hz."

Frequency of vertical input :  2500.0 Hz.

Example 15.9 , Page Number 549

In [2]:
#Variables

div = 1.0                   #One division = one cm (in cm)
mark = 0.4                  #One mark (in cm)
space = 1.6                 #One space (in cm)
Amp = 2.15                  #Amplitude 
Ampctrl = 0.2               #Signal amplitude control (in volt per division) 
tbctrlset = 10.0 * 10**-6   #Time based control setting (in seconds)

#Calculation

MtoS = mark/space            #Mark to space ratio
T = (space + mark)*tbctrlset #Pulse time period (in seconds)
f = 1/T                      #Pulse frequency (in Hertz)
Vp = Amp * Ampctrl           #Magnitude of pulse voltage (in volts) 

#Result

print "Mark to Space ratio : ",round(MtoS,2),"."
print "Pulse frequency : ",(f*10**-3),"kHz."
print "Magnitude of pulse voltage : ",Vp,"V."

Mark to Space ratio :  0.25 .
Pulse frequency :  50.0 kHz.
Magnitude of pulse voltage :  0.43 V.

Example 15.10 , Page Number 550

In [1]:
#Variables

L = 10                            #Length of trace (in cm)
S = 5                             #Deflection sensitivty (in volt per cm)

#Calculation

Vpktopk = L*S                     #Voltage peak-to-peak (in volts)
Vpeak = Vpktopk/2                 #Peak value of voltage (in volts)
Vrms = Vpeak/2**0.5               #RMS of peak value (in volts) 

#Result

print "RMS value of ac voltage : ",round(Vrms,3),"V."

#Slight variations due to higher precision.

RMS value of ac voltage :  17.678 V.