Abstract: An adaptive threshold circuit for use with a magnetic type of sensor that has a pick-up coil. The pick-up coil has an alternating voltage induced therein when a slot formed in a wheel rotates past the sensor. The circuit produces a square wave pulse voltage during positive half-cycles of the voltage generated in the pick-up coil. The circuit includes a digital to analog converter the input of which is connected to a pulse counter. The output of the converter is a function of the count magnitude in the counter and provides a variable threshold voltage that is compared by a voltage comparator with a voltage that is a function of the magnitude of the voltage generated in the pick-up coil. The circuit has an input circuit connected to the pick-up coil that includes a voltage attenuating circuit and a diode.

Abstract: A trans-dermal medication application cell for temporary attachment to the skin of a patient to facilitate the diffusion of medication solution from the cell's interior to the skin of a patient where it will be absorbed. A housing non-reactive with medication solutions is closed by a micro-porous diaphragm or membrane. A formed perforated medical foam sheet is secured to the housing and, in use, to the skin of a patient by a medical adhesive. A release sheet and vapor barrier secured to the foam sheet block exterior access to the micro-porous membrane and adhesive coated foam sheet prior to application to the patient's skin. A self locking and sealing plug closes the filling aperture in the housing in the principal invention embodiment.

Abstract: A medication application system comprising a container for medication adhesively secured to the unbroken skin of a patient. The container is cup-shaped and closed on its open side by a micro-porous diaphragm or membrane through which the medication passes from the container to the skin surface where it is absorbed. Particular means are described for adhering the container to the skin and for sealing the container prior to its use. Various pharmaceutically effective medications in differing concentrations found to be effectively dispensed from the container, are described.