Pickering Interfaces Limited

Keith Thomas Moore

David P Owen

Adam Charles Mitchell

An array of reed switches () is assembled on a circuit board () having a plurality of through-apertures () with one reed switch () disposed in each aperture with the axis of the switch envelope () extending perpendicularly to the plane of the board. A plurality of coils () is provided on the board so that each switch () is surrounded by a respective coil, the coils being connected to conductors on the board for operation of the switches. Also disposed is a control circuit wherein the reed switch drive coils () are connected in series across a constant-current voltage source and a respective solid-state switch TR, TR. . . connected across each coil, with divers for each solid-state switch to permit operation of a selected reed switch.

Reed switch arrays

A variable resistor network has a coarse resistance network and a fine resistance network connected in series with the coarse network. The coarse resistance network comprises a chain of series-connected resistors any one or more of which may be switched out of the series by individual parallel-connected relays. The fine network comprises a shunt resistor together with a fixed resistor and a series-connected adjustable resistor together connected in parallel with the shunt resistor. A control circuit is arranged to control the relays for the switching of the resistors of the coarse network and also to control adjustment of the adjustable resistor. A chosen resistance value can be set by appropriate switching of the coarse network and adjustment of the adjustable resistor.

Growing community of inventors

Bradfield, United Kingdom

Keith Thomas Moore