The Keithley Model 7753 is a 1MOhm High Voltage Source/Switch Module. The Keithley 7753 module includes programmable DC voltage (50-500V) and current (0-50mA) sources, as well as relay switching. A built-in current-to-voltage converter on this module is used with the voltage source to measure the insulation resistance. It can also be used to measure currents from 0-50A. The switch matrix of the Model 7753 simplifies implementing contact verification tests and allows the Model 2790 to verify test voltages and currents for increased measurement reliability.