Sundstrand Data Control, Inc.

Walter Kamphorst

Henry J Lukes

Romeal F Asmar

A charge amplifier having minimum offset voltage such as for use in processing a signal from a capacitive transducer. The amplifier is arranged to minimize the offset voltage and drift. The amplifier is arranged to be reset to zero upon application of supply voltage thereto, and the resetting circuit is arranged to reset the amplifier automatically during an adjustable interval after application of the supply voltage. The charge amplifier is further compensated for temperature variation and is arranged at minimum offset voltage notwithstanding strong background noise.The amplifier is arranged to have a drift of no more than a fraction of a millivolt per second. The amplifier circuit includes an improved switching arrangement and may utilize a second amplifier circuit for effecting temperature compensation.

Charge amplifier with minimum offset voltage

Direct readings of the timing angle and duration of the fuel injection of a diesel engine along with the engine speed are provided by an electronic test instrument that converts the duration of the timing advance and the duration of one engine revolution into electrical pulses of corresponding width. Both these pulse widths are then converted to corresponding electrical quantities and the quantity which corresponds to the timing angle is divided by the quantity which corresponds to one engine revolution to produce an indication of timing angle, or alternatively a constant reference quantity is divided by the quantity which corresponds to the engine revolution, thus providing an indication the engine speed.

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Redmond, WA, United States of America

Walter Kamphorst