Skin test device using I.C. comparator circuit

Claim 1

A portable device for testing skin or scalp resistance to determine an oily, normal and dry skin condition, comprising: a. a battery driven bridge circuit providing preset, fixed resistances in a first set of adjacent legs of the bridge circuit; b. a skin surface probe-touchplate and battery drain resistance in a second set of adjacent legs of the bridge circuit opposed to the first set of legs, the probe-touchplate being adapted to test an area of skin for resistance corresponding to the skin condition; c. a plurality of I.C. comparators connected in the bridge circuit adapted to turn on and off when comparing with a skin resistance that is equivalent to oily, normal and dry of respectively about: 15K-18K; 30K-35K; and, 42K-50K ohms corresponding to the fixed resistances in the first set of legs of the bridge circuit; d. light indicators associated with each of the comparators for instantaneous actuation when the associated comparator changes state; and, e. biasing resistances associated between each comparator and its associated light indicator; the battery voltage for driving the bridge circuit, comparators and light indicators being about 5-12 volts; whereby: i. the light indicators serially activate when the comparators change state upon equalling the resistance associated with a particular skin condition; and, ii. when a skin resistance occurs between resistances defining the particular skin condition, thereby activating two light indicators, a selection is made based primarily on which light indicator is initially actuated, and secondarily on which light indicator is subsequently actuated.