Abstract: There is provided a voltage monitor which monitors a first voltage. A means for providing a reference second voltage is provided. Also, a signal third voltage which is obtained from and is proportional to the first voltage is provided. A comparison amplifier for comparing the reference second voltage and the signal third voltage produces an output voltage which goes to a first polarity when the signal third voltage exceeds the reference second voltage and which goes to a second polarity when the signal third voltage is less than the reference second voltage. Also, there is provided at least one indicator and at least one driver amplifier which amplifies the output voltage and drives the indicator into a first state when the output voltage shows that the signal third voltage exceeds the reference second voltage, and drives the indicator into a second state when the output shows that the signal third voltage is less than the reference second voltage.

Abstract: An amplifier circuit having an input circuit of resistance and capacitance which is a.c. coupled to a source of pulses, and a feedback circuit of resistance and capacitance. The RC time constants of the input and the feedback circuits are made to be approximately equal at the time of pulse input in order to insure an output pulse flat base line without undershoot or overshoot.

Abstract: A method for monitoring characteristics of a magnetic recording head which is flying in an air bearing relationship over a rotating magnetic recording disk containing Fe.sub.2 O.sub.3 detects triboelectric charges generated by intermittent contact between the head and the disk and also detects modulations in the spacing between the head and the disk surface when the two are not in contact.

Abstract: A float assembly for a sensor provides a float member having a channel passing therethrough, a mounting for the sensor on the float, a guide passing through the channel for guiding the movement of the float member, a stop including a magnet located on the guide for limiting the movement of the float, and a magnetically activated switch included in the float member for activating when in proximity to the stop magnet for indicating that the float member is in proximity to the stop.

Abstract: An electrostatic system analyzer for checking the voltage at various test points in a high voltage electrostatic spray coating system. The analyzer is in the form of a gun having a telescoping cylindrical barrel with an exposed electrode at its forward end, and a meter at its rearward end, and having a downwardly extending conductive handle. The forward portion of the analyzer body, which is axially and angularly movable relative to the rearward portion, includes a conductive receptacle electrically connected to the electrode, and the rearward, portion of the analyzer body includes four axial bores equidistant from a central axis and equiangularly arrayed thereabout. Each bore contains a resistor, and the resistors are electrically connected in series, with three of the resistors each having an individual plug extending toward the forward analyzer body portion and being receivable for electrical contact within the receptacle when the two portions are telescoped together.

Abstract: A direct-coupled DC amplification circuit effects amplification over all the amplification stages using a ground potential as the reference voltage, and yet supplies a load with voltages in both positive and negative directions. In one preferred embodiment, a second or subsequent amplification stage including a phase compensating element has an amplification element in the form of cascode-connected complementary transistors connected to positive and negative power input terminals via first and second constant current circuits, respectively, and the set current of the first constant current circuit is set to be twice greater than that of the second constant current circuit.

Abstract: In certain types or electrical systems such as pulse modulators, it is extremely important that the systems have a high on/off ratio. To accomplish this, an electrical system is provided having first and second channels coupled in parallel to a frequency source. If the system is a pulse modulator, the first channel is the pulse modulation channel, and includes a first combining means coupled to the carrier frequency source and a modulation input pulse source to produce a pulse modulated output signal with "on" and "off" periods. The second channel includes a second combining means which is coupled to the carrier frequency source and a constant voltage signal to produce a continuous output signal. An inverter is provided in one of the channels to invert the carrier frequency signal going to one of the combining means.

Abstract: A controlled main switch, typically a semiconductor switch, is connected in parallel to the load. In accordance with the invention, an auxiliary switch, typically also a semiconductor switch such as a switching transistor is directly connected across the terminals of the load, and with an impedance, for example a resistance, diode, or Zener diode to the main switch, and controlled to switch in synchronism with the main switch, so that the residual voltage across the load due to inherent voltage drop across the terminals of the switch becomes a minimum. Integrated technology may be used, combining preamplifiers and distribution networks in one monolithic chip.

Abstract: A zener diode having an accurately predetermined breakdown voltage, and a method of making such a zener diode. A discrete device and integrated circuit adaptation of this device is disclosed. A specially highly doped opposite conductivity type island is embedded in a high resistivity body portion. Embedded in the body portion contiguous the island is an ion implanted surface portion of the one conductivity type. The surface portion has an accurately predetermined concentration of conductivity determining impurity atoms in the range of about 1 .times. 10.sup.16 to 1 .times. 10.sup.19 atoms per cubic centimeter. A PN junction having a high breakdown voltage separates the island from the body. A PN junction having a lower but accurately predetermined breakdown voltage separates the island from the surface portion and forms a zener junction. In integrated circuit adaptations, this device preferably shares a transistor electrode for a transistor junction that is to be protected from overvoltage effects.

Abstract: A body of semiconductor material has opposed end surfaces, opposed side surfaces extending to the end surfaces and opposed first and second contact surfaces which are substantially perpendicular to the end and side surfaces. The body includes a substrate having on a surface thereof a mesa shaped active region which extends to the first contact surface. The active region has side surfaces which are spaced from the side surfaces of the body. Also on the substrate are passive regions which extend from the side surfaces of the active region to the first contact surface and side surfaces of the body. The active region has a P-N junction therein. The passive regions each include a plurality of contiguous passive layers having, P-N junctions therebetween. The P-N junctions of the passive regions extend from the first contact surface to the side surface of the body. Metallic electrodes are on each of the contact surfaces. The passive regions serve to restrict current flow to the active region.

Abstract: A radiation sensitive semiconductor device includes a light sensitive region and an independently selectable gate region isolated therefrom. High sensitivity in combination with large permissible light gathering areas are features.

Abstract: An array of collimated wise aperture electrically pumped leaky corrugated AlGaAs optical waveguide lasers is formed on a single chip by etching a series of grooves oriented with respect to the crystalographic planes to isolate discrete lasers in the array and provide the requisite orientation of the internal reflecting surfaces to support the lasing action. The corrugation period is chosen such that the laser radiation exits from the array in a direction normal to the plane of waveguide.

Abstract: In cavity dumped state lasers the relaxation oscillations caused by cavity dumping are stabilized and damped out by placing a non-linear second-harmonic generation crystal inside the optical cavity of the laser and phase-matching it to produce a doubled frequency component of approximately 0.1% that of the circulating power. The degree of damping depends on the conversion percentage, which may be varied by temperature controlling the frequency doubling crystal. A conventional antireflection coating is placed on the crystal to minimize losses.

Abstract: A transistor device is described in which an NPN semiconductor structure has a specially adapted N-type emitter zone and associated electrode. The emitter zone is produced by etching a cavity in one major surface of the semiconductor body followed by diffusion of N-type dopant material. Emitter, base and collector electrodes are then affixed to the appropriate surfaces of the body to provide electrical and thermal contact thereto.

Abstract: A monostable multivibrator having a novel four terminal semiconductor device with a generally V-shaped emitter grounded current amplification characteristic. Means are provided to bias the operation of the device to a low point on the characteristic, to provide a trigger signal to the base of the semiconductor device for placing the device in a conducting state and, through the operation of a capacitor coupled between the gate and collector terminals, to shift the operation of the device to a high level on the emitter-grounded current amplification characteristic thereby sharply decreasing the output voltage obtained at the collector. Discharge circuit means are provided for the capacitor to gradually reduce the gate voltage and to shift the operation of the device back to the low circuit point thereby reducing the collector current and suddenly increasing the collector voltage.

Abstract: Selected circuit elements and interconnections of a integrated circuit device are connected by platinum silicide fuse links which open when electrical power exceeds a threshold amount. The fuse is constructed by defining the fuse geometry in a polycrystalline silicon layer over a wafer substrate, depositing a layer of platinum thereover and then sintering the platinum into the polysilicon.

Abstract: A method for making an electrolytic capacitor. A valve metal powder of the sponge type is compressed into a compact body and other usual steps including anodization and electrode application are carried out thereon. Mainly due to the use of sponge type valve metal powder, this method makes it unnecessary to carry out the conventionally employed step of sintering the compact body and produces an electrolytic capacitor having properties better than those obtained by the conventional method. This invention also provides an electrolytic capacitor characterized by the use of sponge type valve metal powder and specific lubricant materials.

Abstract: A novel circuit is provided for controlling an alternating current supplied to a load which includes a variable impedance element in the form of a low emitter concentration transistor which is bidirectional, and which has a high gain. The impedance of the variable impedance element to the flow of current therethrough is substantially the same in either direction of current flow.

Abstract: A frequency converter utilizing a novel four terminal semiconductor device having an emitter grounded current amplification characteristic which is V-shaped wherein the gate terminal of the four terminal device is biased to the low point of the emitter grounded current amplification characteristic and wherein a signal which varies in time is applied to the gate terminal to cause the emitter grounded current amplification factor to fluctuate at both sides of its low point. A tuning circuit is provided in series with the emitter-collector terminals of the four terminal device and is tuned to twice the frequency of the input signal applied to the gate terminal.

Abstract: Disclosed is a radiation emitting diode in which a first layer of N-type GaAs and a second layer of N-type GaAlAs are formed on an N-type GaAs substrate. A localized zinc diffused region extends through the second layer and partially into the first layer to form a buried junction. Because of the higher bandgap energy of GaAlAs than of GaAs, the current density in the GaAlAs portion of the p-n junction is greatly reduced compared to that in the GaAs portion and the non-radiative surface components of current are greatly reduced. This results in a buried junction structure in which the radiation emitting region is removed from the surface. The buried junction structure provides devices having improved linearity of the radiant output power versus current characteristics and reduced degradation of radiant output power at constant current with time.