Abstract: A solderable metal layer is chemically deposited as an electrical contact on a solid-electrolyte capacitor by replacing the conventional silver contact layer of the capacitor with a layer of colloidal carbon containing a metal which is more electropositive than the solderable metal to be deposited, and thereafter contacting the assembly with a salt solution of the solderable metal. The metal of the salt solution is chemically replaced by the more electropositive metal so that the solderable metal plates out on the carbon surface to form the desired solderable contact layer. The salt solution is preferably a copper or nickel salt solution, and the more electropositive metal is preferably iron.

Abstract: High voltage integrated circuit field plates that are connected directly to the epitaxial pockets over which they lie, are formed simultaneously with high resistivity polysilicon resistors and are insulated from cross-over metal by a dual insulation of silicon dioxide and silicon nitride. Without adding to these process steps, MNS capacitors are formed that have a higher packing density than their MOS counterparts. The space saving MNS capacitors are thus space-wise and process-wise compatible with the polysilicon field plates that occupy much less chip real estate than do diffused channel stops.

Abstract: A solid electrolytic capacitor is manufactured by screen printing a layer of valve metal powder ink in an array of pads, placing a valve metal pellet on end on each pad, and sintering the resulting assembly to produce an array of porous sintered pellets bonded through a graded density layer to said substrate. Next the assembly is electrolytically anodized to form a valve metal oxide over its surfaces. An insulating polymer may be applied to the substrate around the pellets, and the pellets are impregnated and coated with manganese dioxide. A conductive layer and counterelectrode are applied over the manganese dioxide, and the anodic oxide is removed from the reverse side of the substrate. The array may be separated into individual capacitors.

Abstract: A sawtooth-voltage-generating oscillator has a high gain comparator circuit formed of two differentially-connected NPN transistors driven respectively by two PNP transistors that leads to a very linear ramping of the sawtooth waveform, and at the same time, provides a sawtooth voltage swing at low supply voltages that may be within no more than 1.5 volts less than that low supply voltage. This oscillator also has the capability of working in the feed forward mode in a switching mode power supply while maintaining a stable oscillation frequency over a wide range of supply voltages.

Abstract: An aluminum electrolytic capacitor has a wound foil section with cellulosic spacer material, interleaved between and contiguously wound with the foils, loaded with 1 to 6 wt % of a synthetic hydrotalcite. The spacer material may be Manila, Kraft or Benares paper.

Abstract: A large number of equally spaced Hall-sensors form a column. They are mounted in a tube with a closed bottom. Each sensor is a packaged integrated circuit with a Hall-cell connected to a Schmitt Trigger circuit. An annular float being fitted slidably about the tube carries a compound magnet that generates a pattern of regularly spaced apart magnetic field regions each having the same dimensions and each capable of switching an immediately adjacent Hall-sensor. The Hall-sensors are energized sequentially and one at one time. By counting the number of Hall-sensors scanned, from the beginning end of the column to the first Hall-sensor that is switched, a rough measure of the liquid level is obtained. The magnetic field regions are spaced apart by a distance that is not equal to the Hall-sensor spacing so that the pattern of Hall-sensor output voltages provides a unique vernier measure of the liquid level that is appropriately added to the afore-said rough measure.

Abstract: Aluminum capacitor foil is etched by passing it through a bath of electrolyte under the influence of pulsed direct current. The pulse duration is at least nine times as long as the interval between pulses when the current falls to zero and is preferably 3 to 27 milliseconds. The pulse current density is 2 to 10 A/in.sup.2, etching temperature is 50.degree. to 90.degree. C., and the electrolyte is an aqueous solution containing sodium chloride and sodium sulfate.

Abstract: Aluminum electrolytic capacitor foil is etched by first subjecting high-cubicity foil to a chemical etching stage in which the etchant is an acidic aqueous solution containing an acid having anions for anodizing aluminum, hydrochloric acid, transition metal ions, and aluminum ions. Preferably, the anodizing anions are present in a greater concentration than the chloride ions. The foil is then subjected to a second etching step which may be chemical or electrochemical. The process produces a high capacitance foil with high bend strength.

Abstract: Aluminum capacitor foil which has been etched for low-voltage applications is rendered usable in intermediate to high voltage capacitors by anodizing the foil in two-stages; first a low voltage stage in an adipate electrolyte and then a higher voltage stage in a borate electrolyte. The fine etch structure of the low-voltage etch is thereby not plugged in the second, higher voltage formation stage, whereby the foil is suitable for intermediate to high-voltage capacitor use.

Abstract: An integrated circuit AM radio receiver includes a scan-tuner comprised of a frequency synthesizer with micro-processor controller. The tuner stops scanning when an AGC derived signal increases beyond a predetermined level indicating a strong station and additionally when another signal falls below a predetermined level indicating that the radio is accurately tuned to the station frequency. The another signal is derived from an FM discriminator simultaneously using the same coil as is employed for tuning the last AM-IF stage.

Abstract: A dry metallized film capacitor which includes an interrupter is potted with a plasticized urethane containing unreacted isocyanate groups. Sufficient plasticizer is used so that the potting material is soft enough to permit functioning of the interrupter and is also viscous enough to remain in place to prevent spillage under leakage or rupture conditions.

Abstract: A radio receiver has one or more automatic gain control (AGC) circuits that each generate the gain-determining bias current in a separate main channel section or sections, e.g. RF amplifier, mixer, IF amplifier, of the radio receiver. The receiver is for the most part formed in an integrated silicon circuit, wherein the gain-controlling current in each case biases the base-emitter junction of an amplifying grounded-emitter transistor so that the gain thereof is directly proportional to the magnitude of the AGC control current. That current in each case is caused to flow through a diode string to generate a voltage drop thereacross that is logarithmic function of the AGC control current as well as of the radio signal amplitude at the input of the AGC controlled section. The sum of those diode voltages may be taken to produce a log of the product of the gains of the AGC controlled sections. Thus a sum signal is a logarithmic function of the radio signal input to the receiver.

Abstract: In an aluminum foil electrolytic capacitor, the anode foil bears both a layer of hydrous aluminum oxide and a layer of barrier dielectric oxide and is in contact with an electrolyte containing as additives up to 5 wt % depolarizer and sufficient soluble phosphate salt to restore the desired anodization voltage.

Abstract: In an integrated AM-FM radio circuit connected for operation in the FM mode, the voltage appearing across the normally unused AM tank at the IF amplifier is noise in that AM band centered at 455 KHz. That noise, which is present only when the IF amplifier is not limiting due to the presence of an FM signal therein, is used for muting the receiver. The noise is passed through a simple IC-on-board low pass filter to a noise detector and then to a voltage controlled attenuator to attenuate the demodulated audio from the FM detector to the audio amplifier.

Abstract: A silicon integrated circuit includes a centrally located Hall element having an annular moat region surrounding the Hall element to isolate it from built in stresses in adjacent parts of the integrated circuit. The moat comprises at least one annular isolation wall, but preferably two concentric isolation walls. This moat construction also leads to a reduction in dependency of Hall element symmetry upon process variables.

Abstract: A self regulating ceramic PTCR (positive temperature coefficient of resistance) heater has a pair of spaced interdigitated electrodes on one major surface of a ceramic PTCR plate. A heat transfer means is provided for extracting heat from the opposite major surface of the PTCR plate. Best heating efficiency is obtained when the thickness of the PTCR plate is about the same or is less than the average spacing between the electrodes.

Abstract: Pure silver and palladium powders are thoroughly mixed and dispersed by ball milling in a solution of a surfactant in a liquid vehicle. After drying and granulating, the resulting powder was heated to 500.degree. C., first to form an Ag/Pd alloy powder and then to cause palladium to precipitate from the interior of the alloy particles, to form a protective barrier of PdO on the alloy particle surfaces and to alter the alloy to 90Ag/10Pd. This powder, when used to make a buried electrode in a ceramic capacitor changes dimensions very little up to 500.degree. C. in the early stage of sintering the ceramic below which temperature the ceramic is weakest and most subject to cleaving.

Abstract: An AC wound metallized film capacitor which has a tab connected to each electrode utilizes a unitary spacer which encompasses the wound section isolating the section from a metal housing and the tabs from each other. The spacer is mainly rectangular in shape with a rectangular extension near the end of one long side and a cutout opposite the extension on the opposite long side. The spacer is wrapped around the capacitor section overlapping itself and extends beyond the top and bottom of the section. One tab, which is attached at the bottom of the section, passes between wound layers of the spacer and extends beyond the upper end of the section. The spacer extending beyond the bottom edge of the section is folded and sealed. The rectangular extension of the spacer isolates the bottom tab from the top of the section.

Abstract: A capacitor assembly has a wound and flattened non-extended foil capacitor section with at least one electrode tab connected to each electrode and is enclosed in a case having an insulating cover and an insulating base. Conductive members are secured to said base by conductive means which extend through the members and the base; one end of each conductive means is covered by a folded portion of the conductive member and welded. The electrode tabs are attached by welding to a side portion of the conductive member.

Abstract: An aluminum electrolytic capacitor has a capacitor section of two aluminum electrode foils, at least one of which bears a barrier layer anodic oxide, wound with interleaved spacer material in contact with an electrolyte containing a phosphate salt, the cation of which is compatible with the cation of the electrolyte solute to prevent precipitation of a phosphate.