Abstract: An improved beginning-of-tape/end-of-tape sensor for magnetic recording apparatus includes a metalic foil strip adhered to the reverse side of the magnetic record, the opposite side from the oxide, and positioned at the desired longitudinal positions on the tape. A pair of capacitive detectors are positioned adjacent the oxide surface of the tape to detect a change in capacitance when the metalic foil on the opposite side of the tape effectively bridges the two capacitive detectors. A digital logic comparator is provided for responding to the capacitance change to produce a signal representative of the beginning of tape or end of tape condition.

Abstract: There has been provided an improved switching circuit for an oscillographic apparatus wherein a determining wave form signal is compared with a reference level signal to provide a trigger control signal. The trigger control signal, a low level signal, is selectively gated to produce a signal in response, selectively, to the negative slope comparison or the positive slope comparison. The last-mentioned signal is then used to produce a trigger signal to trigger a sweep signal generator for the oscillographic apparatus.