摘要:
A method of making wire wound electrical resistance elements comprising the steps of winding a respective resistance wire helically around and along each of a plurality of elongated wire cores which cores are coated with an insulating material, coating each of said wound cores with a protective layer, arranging said wound cores in closely spaced parallel relation, encapsulating said arranged wire cores in a block of plastic material, cutting through the block and the wound cores at longitudinally spaced points along planes perpendicular to the longitudinal axes of the wound cores to form a plurality of wafers each of which contains a plurality of resistance elements, and then separating said resistance elements from the plastic of the respective wafers. The disclosure also includes the steps in which prior to separating resistance elements from the plastic of the wafer, the ends of the wire cores are contacted with an etchant to etch away a portion of the ends of the wire cores, after which the ends are coated with a film of an insulating material.
摘要:
A pulse-actuated reed switching matrix of the magnetically latching type in which the reed capsules are mounted flat on a printed circuit board providing the appropriate speech path connections, has row and column windings which are respectively printed on two substrates disposed in planes parallel to that of the reed capsules. The two substrates are formed by two sections of a flexible sheet of insulating material which are folded over each other so that the points of intersection of the column and row windings - control locations - register with one of the two contact blades of the reed capsule or capsules at the corresponding crosspoint while the other blade of each reed capsule is provided in a magnetic bias location of the matrix. Two embodiments are shown. In the first the reeds are of lowremanence magnetic material and a plate of semi-hard magnetic material, sandwiched between the two sections of the above flexible sheet has, interposed between its rows of control locations, rows of bias locations in which the plate is magnetically pre-polarized through its thickness in alternating directions. In the second embodiment each reed capsule has a reed blade of semi-hard magnetic material in the corresponding control location of the matrix, whereas the cooperating reed blade in the respective bias location is of permanent magnetic material. In both implementations coincident current selection is employed, and the pulses used for operating and for releasing a selected crosspoint are of opposite directions.
摘要:
A flexible membrane is disclosed which extends over an aperture in a support plate in an electromagnetic sealed contact matrix or ferreed type switch. The ferreed switch includes at least one circuit path element and the flexible membrane joins the circuit path element to the support plate and extends the circuit path element over the aperture to a point of rigid contact with a conductor lead projecting from an associated sealed contact switch.
摘要:
A compound switching matrix (30) operates in cooperation with a resistance measuring system (20) and a laser (22) to quickly and accurately trim resistors (12) to predetermined values while they are being measured. The compound switching matrix is implemented with dry reed relays (34-81, 101-164) and includes a probe switching matrix (90-97) and a configuration matrix (32) that reduce the average number of relay contacts required per probe to implement two-, three-, and four-terminal measurements with or without guarding. Moreover, the separate probe switching and measurement configuration matrices effectively separate the high and low sides of the measurement to reduce the effects of stray resistances and capacitances on measurement speed and accuracy. A switchable grounding configuration (82-89) further improves measurement accuracy. The compound switching matrix of this invention enables sequential resistance measurements of individual resistors in the array, with two-, three-, and four-terminal measurement configurations being adapted to resistors having values ranging from less than 0.1 ohm to greater than 100 Megohms.
摘要:
Switch comprising a matrix of relays, each providing a connection point between a horizontal input and a vertical input, and auxiliary control relays, at least one per vertical input, fulfilling the horizontal and vertical input control functions and the holding of the vertical input control and the releasing of the horizontal input control.