# CHAPTER 23 : INTEGRATED CIRCUITS¶

## Example 23.1: Page number 637¶

In [1]:
#Variable declaration
R1=240;                     #Adjusted resistance of R2 resistor of LM317 voltage regulator, in kilo ohm
R2=2.4;                     #Fixed value of R1 resistor of LM317 voltage regulator, in ohm

#Calculations
#Output voltage of LM317 voltage regulator IC = 1.25(R2/R1 +1)
Vout=1.25*((R2*1000)/R1 + 1);                      #Regulated d.c output voltage for the circuit in V

#Results
print("The regulated d.c output voltage = %.2fV"%Vout);

The regulated d.c output voltage = 13.75V


## Example 23.2 : Page number 638¶

In [2]:
#Variable declaration
R=1.2;                  #Value of resistance of monostable multivibrator in kilo ohm
C=0.1;                  #Value of capacitance of monostable multivibrator in microfarad

#Calculations
T=1.1*(R*1000)*C;              #Time for which the circuit is ON, in microseconds

#Results
print("Time for which the circuit is ON = %d microseconds."%T);

Time for which the circuit is ON = 132 microseconds.


## Example 23.3 : Page number 639¶

In [3]:
#Variable declaration
R1=3.0;                       #Resistance of R1 resistor of 555 timer circuit in kilo ohm
R2=2.7;                       #Resistance of R2 resistor of 555 timer circuit in kilo ohm
C=0.033;                      #Capacitance of the capacitor of 555 timer circuit in microfarad

#Calculations
f=1.44/(((R1*1000) + 2*(R2*1000))*(C*pow(10,-6)));                   #Frequency of the circuit in Hz
f=f/1000;                                                            #Frequency of the circuit in kHz

#Results
print("The frequency of the circuit = %.2fkHz"%f);

The frequency of the circuit = 5.19kHz