Abstract: Apparatus for testing electronic devices having a high density array of pin leads includes a zero insertion force socket having coaxial output leads with the inner conductor being a conductor pair with the coaxial lead terminating at a number of test heads. Each test head includes switching means for terminating the output coaxial lead in a characteristic impedance. The various test heads are then coaxially coupled, maintaining the two conductor inner lead pair, to more distant signal sources and receivers of both the ac and dc types to provide for Kelvin testing by separately connecting the inner conductor pair to power and sense devices or shorting the conductor pair together and conducting ac testing by use of pulsers and discriminators, or other dynamic test sources or sense devices such as sinewave devices.

Abstract: A plug-in zero insertion force type socket for making temporary electrical connection between the leads on a semiconductor device and testing circuitry where each connection between the high density array of semiconductor device leads and testing circuitry is shielded from external radiation to eliminate cross talk and capacitance coupling. Transit time effects on the shielded electrical connections are minimized by providing short electrical connections which include a high density flared array of coaxial leads connecting a multi-planar arrangement of testing circuitry to the socket.