To simply set a time constant and even a time as desired without using an exclusive jig at all.

The resistance of fixed resistors R1-R5 being components of a resistance circuit 1 is known in advance. Then each time constant depending on switches SW1-SW4 that are open/closed is known in advance. Thus, in the case of adjusting the time constant of the circuit to be a desired value, it is conducted by having only to property turning on/off the concerned switches SW1-SW4 and then no exclusive jig is required at all.