067-0077-00
The Tektronix 067-0077-00 is a square wave calibrator for checking the calibrator circuits in scopes. It contains a precision voltage divider which it uses to get voltages in the standard 1-2-5 sequence between 0.2 mV and 100 V.
An internal relay switches between between the divided reference voltage and an external unknown voltage which is applied to the 067-0077-00.
The 067-0077-00 might be the precursor to the 067-0502-01.
