A power-up circuit includes a power-up signal generating section connected to an external source terminal, configured to generate a power-up signal when the external source reaches a predetermined target level, and to selectively interrupt a path from the external source terminal in response to a selection signal. The enclosure includes a cover that is moveably attached to a main body in a manner whereby the main body and the cover jointly define enclosable interior space of the enclosure. The test sensor can be fabricated to support interdigitated arrays of electrodes that have been designed to provide amplification of the electrical signal amplification desired to analyze analytes that may be present at low concentrations.