# Chapter4 Series and Parallel Connection of Thyristors¶

## Example 4.1,Pg.no 13¶

In :
import math
Vc=3500    #voltage rating of circuit
Vt=750     #voltage rating of each thyristor
Ic=1500    #current rating of circuit
It=500     #current rating of each thyristor
DF=0.1     #Derating factor of circuit
Ns=Vc/(Vt*(1-DF))   #number of devices in series
Ns=round(Ns,0)
print 'Number of Devices in Series=',Ns
Np=Ic/(It*(1-DF))   #number of devices in parallel
Np=round(Np,0)
print 'Number of Devices in Parallel=',Np

Number of Devices in Series= 5.0
Number of Devices in Parallel= 3.0


## Example 4.2,Pg.no 13¶

In :
import math
Ed=20.0    #permissible difference in voltage across devices in Volts
Id=1*10**-3   #maximum difference in latching current across devices in Amperes
Qd=10.0          #difference in recovery charge in Micro coloumbs
Vd=20.0         #permissible difference in blocking voltage in Volts
R=Ed/Id       #equivalent resistance in Ohms
R1=R
print 'value of equivalent resistance=R=',R1,'ohms'
C1=Qd/Vd   #equivalent capacitance in Micro farads

value of equivalent resistance=R= 20000.0 ohms