Find out through an internet research, how the instrumentation amplifier works.

1. Consider the illustrated Falstad Simulation below and change the variable resistance. Especially analyze the minimum and maximum value of the output voltage. This is possible by moving with the mouse pointer over the output signal.
2. What happens if you remove the variable resistance and leave the connections open? Which circuit have the OPVs at the entrance?
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
3. Compare the following situations. What is to be determined?
   1. Variable resistance is replaced by resistance with 2 kOhm.
   2. Variable resistance is replaced at the top connection by $1 k\Omega$ against mass and below by 1 kohm against mass.
   3. Variable resistance is replaced at the top connection by $1 k\Omega$ against a voltage source with 1 V and below by 1 kOhm against 1 V.
      
      
      
      
      
      
      
      
      
      
      
      
      
      
      
      
      
      
      
      
      
      
      
      
4. Which transfer equation does the initial construction, if all resistances (up to the variable resistance $R_G$) have the same value $R$? $U_A=F(U_2,U_1,R_G,R)=?$
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
5. What are the advantages for the instrumentation amplifier to the differential amplifier?