A switch subsystem may be called upon to switch signals from DC to over 25 GHz, millivolts to thousands of volts, and milliamps to amps. It may even be required to switch optical signals. The loads can be resistive, inductive, capacitive, or a combination of these. The switch subsystem is often expected to automatically supply power to a device under test (DUT), connect specific stimuli to appropriate inputs, connect various points of the DUT to measurement equipment at various times, and then remove power.

With such a wide range of requirements expected of the switch subsystem, it is not surprising that there are many switch topology options. To select the proper topology including the proper type of switch, an engineer naturally must know what is to be tested, how the test is to be conducted, and how often the test or tested device needs to be changed. These test parameters dictate the configuration of the test system, which in turn affects the design of the switch subsystem.