Abstract: For appropriately polarity recognition and corresponding switchover of a output stage of a proximity switch or the like connected to a supply voltage (VB), even while continuously activated, when a change in load polarity occurs, the proximity switch having in each case a high side driver and a low side driver, it is proposed to define on the output-side voltage axis between the positive supply voltage (+VB) and the negative pole or ground an upper and a lower detection window which sense the load configuration, each at a distance from the working points (which remain in a steady state) of each output stage driver, such that when a change in load configuration occurs, the potential of the output connection, to which the load configuration detection stage is connected, passes only briefly through these detection windows, and such that the transient signal changes which result therefrom in each window region are used for appropriately polarized switchover to the respective correct output stage circuit section b

Abstract: A proximity switch is provided which has a programmable parameter such as a programmable switching threshold and/or programmable switching function. The device is programmable using a digital signal that is applied to a conventional terminal of the proximity switch. For example, the conventional power signal for operating the proximity switch can be modulated by a programming signal for use in programming the proximity switch parameters. The program signal could also be input to a conventional output terminal of the proximity switch.

Abstract: In order to improve a proximity switch insensitive to interference fields r detecting the position of a machine element with at least one sensor which generates in the proximity of a machine element standing in a position to be detected a total signal having a detection field signal component caused by the machine element and an interference field signal component caused by the interference field and transmits it to a circuit which converts the total signal into an output signal, such that both the gradients of the detection field generated by the machine element and the gradients of the interference field do not affect response of the proximity switch, it is suggested that the conversion of the total signal into the output signal be carried out by the time dependence of the interference field being determined, by a corresponding sequence of scanning pulses being obtained therefrom and the first signal being scanned with these, and by a value which is determined thereby resulting in an output signal indicatin

Abstract: The invention relates to a two-wire switch with a power transistor, in pacular, a VMOS transistor which is arranged in series with an auxiliary impedance between two switch connection lines. In accordance with the invention, a logic circuit with an OR function and an AND function is used in the realization of a kind of phase angle control for the power transistor in the presence of an activating signal of an initiator at the switch input.

Abstract: The invention relates to a two-wire switch for connecting a load to an ac ltage source, and, in particular, to a two-wire switch with an auxiliary voltage source. A capacitor acting as charge storage device can be charged by the auxiliary voltage source which operates on the principle of phase angle control. In accordance with the invention, a series connection comprising a threshold element which can be brought into the conducting state when there is a prescribed minimum voltage across the capacitor, and a diode is inserted into a control current circuit for a controllable semiconductor device on the input side of the bridge.

Abstract: The invention relates to a self-testing proximity switch, wherein the testing is carried out with the aid of bipolar double pulses which, independently of the switching state of the trigger stage, each time cause a short-timed triggering thereof. At the output of the trigger stage, the superimposed pulses can be evaluated by the test circuit in order to monitor proper functioning of the proximity switch.

Abstract: The invention relates to a testing and evaluating circuit for a proximity itch suitable for testing and provided as an element of a machine control means; associated with the proximity switch is a control circuit, by which the proximity switch is alternately switchable between its two operating conditions to generate a timed output signal with a given frequency, an evaluating circuit being provided, by which a clear signal indicating fault-free operation is producable for the duration of a timed output signal from the proximity switch and by which a blocking signal for the machine control means, indicating a fault, is producable in the absence of changes in the potential of the output signal from the proximity switch. The evaluating circuit preferably comprises a relay circuit, to which the output signal from the proximity switch or a signal derived from this is fed via a transformer.

Abstract: An inductive proximity switch with a built-in testing circuit for monitoring movable elements in which an oscillator has an inductive control element, the impedance of which varies in response to approaching elements with a built-in electrical tester for monitoring the correct functioning of the proximity switch wherein the tester has an electrically switchable damping circuit for damping the oscillator for test purposes.

Abstract: To provide an undistorted square wave output signal under control of a switch subject to contact chatter so that the square wave will accurately reflect the operating instant of the switch, as commanded, regardless of contact chatter, a timing circuit is provided having a timing capacitor and a charge and discharge circuit therefor, connected to a threshold circuit, the threshold circuit response level and the charge circuit of the timing capacitor being dimensioned to cause the capacitor to charge to a level such that the threshold circuit responds only when the switch has changed state, typically closed after interrupting an inductive load, such as the primary of a spark plug, for a predetermined time period as determined by the switch contact chatter characteristics of the switch itself, for example about 0.