A metal film less than 100 Angstroms thick is deposited on one face of a semiconductor substrate to form a Schottky-barrier diode. Photons absorbed in the metal form electron-hole pairs; and those carriers with sufficient energy, in the right direction to cross the Schottky barrier, cause a current which is proportional to the incident radiant flux.

By sealing the periphery of a printed circuit board, the previously exposed edges of the board are substantially prevented from moisture wicking. This sealing of the periphery can be made concurrently with the plating of through-holes on the board. With this process, current leakage paths due to board moisture wicking within the board is significantly reduced.

A volumeter, in particular for use in liquid chromatography comprises a metering chamber for the volume to be measured. Another chamber is separated from the metering chamber by a resilient diaphragm and forms an electric capacitor. The capacitance of this capacitor is changed in accordance to deviations of the diaphragm from its true position.

By coincidentally injecting a predetermined level of direct current with the transmission of data on a transmission line, multiple signal transmissions on the line can be detected by the presence of a DC level greater than a predetermined level on the line. Once detected, tactics for avoiding multiple signal collision problems can be implemented.

An improved automatic signal levelling circuit for pulsed radio frequency (RF) signals includes a sampling detector to eliminate distortion of the pulse-modulated RF signal.

A package for flat lead transistors is provided in which a raised flange provides structural rigidity to prevent damage to the flat leads of the transistor.

Apparatus is provided which interrupts arithmetic and logical operations defined by a major opcode instruction if the resultant overflows its defined length. One major opcode defines the arithmetic and logical operations between two operands in registers and the result, zero, one, the generated condition or first operand is stored in a register.

A reed switch with high insulation for a very low current measurement system is provided. The reed switch is embodied by coating over its glass-made surface with fluoroplastics materials in order to reduce the leakage current on the surface.

Basic steel rule dies are provided which can be combined to produce a variety of die cut patterns. Each basic die contains sufficient magnetic material to hold it in place on a steel chase during the cutting operation.

The base for an array of piezoelectric crystals contains tungsten particles that are compression-molded in a binder, the size of the particles at and near the surface on which the crystals are mounted being smaller than the size of the particles remote from the surface.