Abstract: In FIGS. 5 and 7, a temperature chamber 4 encloses a centrifugal-fan wheel 8 that is mounted concentric with a test ring 2 such that the fan's radially expelled air, indicated by arrows 12, flows across the ring in parallel with the test ring surfaces and is circulated via heating/cooling elements back to the fan inlet. The test ring includes guide holes 36 and electronic components 32 with terminals 34. It can be rotated via a pin wheel 22 with drive pins 24 that engage in guide holes 36 . A vertically mobile contact head 26 includes guide pins 28 and contact pins 42 that are connected with an external test instrument 51. Each time the ring is rotated a step, the contact head moves down to first engage guide pins 28 with the guide holes 36—thereby accurately aligning the contact pins 42 with the terminals 34—and, upon further down movement, connecting the contact pins 42 with terminals 34.

Abstract: A carriage or dielectric disk (40) has a series of electrical contacts (46, 48) defined by conventional circuit board techniques on upper and lower surfaces around a peripheral edge. Sockets (42, 44) are wave soldered in electrical connection with the electrical contacts. At least the electrical contacts are plated with a hard, dense metal, such as nickel. When components have been frictionally inserted into the sockets, the carriage is placed in a cooling chamber (18). Air of a selected temperature is blown through a central port (22) and directed to flow over the surface of the carriage and the supported components (10). A motor (60) rotates the carriage to move the electrical contacts (46, 48) successively into electrical communication with relatively soft electrical contact springs (58) connected with a test instrument (32). The test circuit measures electrical characteristics or properties of each component at each of a plurality of preselected temperatures.

Abstract: A heterodyne zero-phase detector (A) produces a phase output signal whose phase varies with the phase difference between a selectively variable test signal and the same selectively variable test signal as modified by being applied to a piezoelectric resonator (B). The heterodyne zero-phase detector includes a voltage controlled oscillator (16) for generating the selectively variable test signal, a first balanced mixer (32) for mixing the selectively variable test signal with a selectively variable heterodyne reference signal, a second balanced mixer (34) for mixing the selectively variable test signal as modified by the piezoelectric resonator with the variaable heterodyne reference signal, and a phase detector (50) for receiving the output of the balanced mixers to produce the phase output signal.

Abstract: Apparatus for automatic lapping control, based on imbedding an electrode in a lap plate of a lap machine and including at least one piezoelectric wafer in the lap load. Connected with the electrode is an automatic control circuit used for sensing the resonance frequency of the piezoelectric wafer and for terminating lapping when the resonance frequency reaches a presetable target frequency. Also connected with the electrode is an impedance comparator circuit used for sensing the presence and absence of a piezoelectric wafer at the electrode face and for activating the automatic control circuit in the presence of a wafer and deactivating the control circuit in the absence of a wafer.

Abstract: Vacuum deposition method for adjusting the resonant frequency of piezoelectric resonators wherein the speed and accuracy of the process are enhanced by abrupt termination of the deposition through injection of a gas into the vacuum chamber at the end of the adjustment cycle.