This invention relates to thick film circuits in which thick film conductors and resistance elements are deposited on a flat base plate of insulating material and in which a lead frame having a plurality of leads has, in the past, been soldered to minor peripheral portions of the thick film conductors to provide external circuit connections therefor. In the past, the current carrying capacity of such circuits was limited to a relatively low value due to the relatively low current carrying capacity of the thick film conductors. Currents in excess of the capacity of the particular conductor will cause the thick film conductors to open due to melting and/or vaporization of the conducting film, thus interrupting current flow therethrough.