With this device the isolation resistance can be calculated. This is used in high voltage systems in cars. The fixed resistors simulate the isolation resistance. The capacitors are there only for filtering. How does it work? Never close both switches at the same time. First close the upper switch from the positive terminal. Wait till the voltage stabilises. Write down the values of both voltmeters. Now open the upper switch and than close the switch to the negatieve terminal. Wait till the voltage stabilises. Write down the values of both voltmeters again. With these values it is possible to calculate the isolation resistance.
