There is provided a portable information terminal having a built-in radio communications device which minimizes a drop in the voltage of a battery and diminishes the operation threshold voltage of the portable information terminal, thereby lengthening the operatable time of the terminal. The first reset circuit asserts a reset signal RS1 when supply voltage VDD ramps up to its rated voltage. The pull tab is a generally planar member having an axially extending shank member with a proximal end portion which can be gripped and pulled by a user and a distal end portion having foot members extending transversely to each side of thereof. A pushbutton may be moved to apply sufficient force to cause the shorter leg to contact the second conductor and the dome to contact the third conductor. The second-conductivity type contact layer has at least a first contact layer, an intermediate second contact layer and a third contact layer stacked in this order and the second contact layer has an impurity density lower than impurity densities of the first and third contact layers. Generally, any additional layersmaterials applied the patient-side of the clear substrate will be substantially transparent to allow light curing of adhesives utilized to connect components to the sensor though the patient-side surface of the sensor during production.