Variable circuit

A variable circuit comprising:

• a switch comprising a plurality of input terminals and a plurality of output terminals;
• and
• an external wiring line,
• wherein the plurality of input terminals comprises a first input terminal to which a first input signal is input and a second input terminal to which a second input signal is input,
• wherein the plurality of output terminals comprises a first output terminal from which a first output signal is output and a second output terminal from which a second output signal is output,
• wherein the switch is configured to form at least one internal connection path electrically connecting any one of the plurality of input terminals to any one of the plurality of output terminals, and
• wherein the external wiring line is outside the switch and is configured to electrically connect the second output terminal to the second input terminal such that the second output signal output from the second output terminal is input to the second input terminal as the second input signal.