Abstract: A method and apparatus for forming refrigerated display cases with both convex and concave curved case sections utilizing a single outer modular member for forming the outer canopy and tank portions of both convex and concave curved sections as well as an inner modular member useful for forming canopy and tank sections of both concave and convex refrigerated display case sections.

Abstract: A method and apparatus for forming refrigerated display cases with both convex and concave curved case sections utilizing a single outer modular member for forming the outer canopy and tank portions of both convex and concave curved sections as well as an inner modular member useful for forming canopy and tank sections of both concave and convex refrigerated display case sections.

Abstract: The position (XY coordinate) of a pointed stylus on a conductive sheet is determined by injecting current from the stylus into the sheet and measuring the current responses at three or more spaced apart electrodes connected to the sheet.

Abstract: A two-terminal rectifier circuit, useful for converting an input a.c. voltage into an output d.c. voltage, is formed by a power MOSFET which is provided with an electrical feedback comparator network designed to turn on the MOSFET once during each a.c. cycle when the input a.c. voltage is nearly equal to its peak positive value.

Abstract: A toroidal, saturable core reactor (14) is connected in series with the conductors (11,19 and 13,21) of a transmission line. A termination network (16) is connected across the transmission line conductors (19,21). In response to an a.c. test signal transmitted from a generator (48) on one of the conductors (11), a series of voltage spikes are induced at the reactor (14) and superimposed on the a.c. test signal. The superimposed a.c. test signal is returned through the termination network (16) and the other line conductor (13) to a current detector (50) for detecting the spikes. A d.c. signal is then applied along with the a.c. signal. If there is a fault beyond the reactor (14), the spikes will be displaced from their expected positions. If there is a fault before reactor (14), the spikes will not be displaced. For ease in signal discrimination against noise, the d.c. signal is modulated.

Abstract: Light-activated power FETs (18, 20, 80, 82) are utilized as switching elements in DC-to-DC converters. The FETs are characterized by high speed and low losses. As a result, the converters are capable of providing very low DC voltages in an efficient low-cost way.

Abstract: An optically controlled bidirectional (bilateral) electrical switch is formed by a pair of photo-Darlington devices connected in series opposing (back-to-back) relationship between the two controlled terminals of the switch. Each of these photo-Darlington devices is shunted by a separate unidirectional diode element, such as a PN junction diode, arranged to conduct current only in the opposite direction from that of current flow through the corresponding shunted photo-Darlington device in its "on" condition. Four embodiments are shown.