The Keithley Model 7064 is a 20-Channel Low-Voltage Scanner Card. The card is designed to introduce a minimum of voltage offset error (less than 1µV differential thermal offset from input to output with copper leads) for sensitive test such as low-level transducer and thermocouple output switching. Channel switching allows one signal to be switched to as many as 20 channels or 20 channels to one channel. In the latter configuration the channels are switched one at a time.