Patent ID: 7468630

Claim:
A combination comprising: first and second terminals for the application thereto of first and second different voltages, respectively; an output terminal; first and second set of devices, each set of said devices having a superconducting state in which it exhibits essentially zero impedance and having a resistive state in which it exhibits measurable impedance; said first set of devices being serially connected between the first terminal and the output terminal; said second set of devices being serially connected between the output terminal and the second terminal; and control means coupled to said first and second sets of devices for selectively setting the first set of devices in the superconducting state and the second set of devices in the resistive state for clamping the voltage at said first terminal to said output terminal and for selectively setting the second set of devices in the superconducting state and the first set of devices in the resistive state for clamping the voltage at said second terminal to said output terminal.