Abstract: A differential transconductance amplifier detects changes of the variable capacitor in a low-impedance, bridge circuit and feeds back current to balance the bridge. The voltage that controls the feedback current is proportional to capacitance over a wide dynamic range.

Abstract: A capacitive measurement circuit detects a change in capacitance between a variable capacitor and a fixed reference capacitor in a bridge network and provides feedback current to null-balance the bridge. Voltage that controls the feedback current is substantially linearly proportional to changes in capacitance over a wide range.

Abstract: A high efficiency high power DC to DC power converter and controller system for a CD ignition system with a simple converter controller (8) for controlling a power switch (2) of a transformer (1) operated as a flyback which includes a lossless snubber (6) and simple current sensor (8a) for sensing and controlling the power converter current, and further including ignition trigger conditioner (9) and phase conditioner (10) for operating a trigger output circuit (11) based on an octal counter (67) for triggering ignition coil circuits of a preferred distributorless ignition circuit of the hybrid ignition system type.

Abstract: A keyboard for an electronic device includes a first key having a touch surface which, in one mode, is responsive to pressing by a user's finger to indicate a selection associated with the first key, and an array of sensors exposed at the touch surface to detect, in another mode, the location where a finger is positioned on the touch surface as an indication of information to be conveyed by a user. The keyboard also includes a second key having an array of sensors which are exposed at a touch surface of the second key and which are sensitive to manipulations of a finger on the touch surface to provide signals used for switching the first key from the one mode to the other mode.

Abstract: A high power high energy distributorless ignition system for multicylinder internal combustion engines using a single energy storage capacitor (4), a single leakage resonating inductor (20) with a switch SS partially or entirely across it, and one or more coils Ti with bi-directional switches Si and with single or double hith voltage outputs, the system defining a compact coil assembly powered by a resonant converter power supply (12), the ignition power delivery controlled by means of circuitry based on a robust gate (17), an oscillator (19), and steering circuitry (21).

Abstract: A portable electronic voting machine suitable for use in simple elections includes a number of spring-loaded switches normally centered and movable upward to a vote position to select a candidate and downward to an erase position to erase a previous selection that has not yet been entered with a light above each switch indicating the state of selection. An n of m counter settable prior to the election to the maximum number of votes that may be cast by a voter and associated logical circuitry prevents more than that selected number from being entered by a single voter. An election official operates a voter enable switch to light a ready light and enables the apparatus to receive vote selections.