Abstract: The present invention is an electronic circuit, such as a Hybrid Integrated Circuit (HIC), having an element mounted on a suitable support base, and a self-adjusting heat sink mounted on the element. A heat spreader is located in spaced relationship with the support base. The heat spreader may be a plate of conductive material provided especially or may form a part of a housing enclosing the HIC. The heat sink has a bottom portion secured to the element and at least one flange for conducting heat energy to the heat spreader. Each flange includes an upright segment projecting from the bottom portion of the heat sink toward the heat spreader, a free end segment bent away from the heat spreader and a knee-bend segment intermediate the upright segment and the free-end segment and adjacent to the heat spreader.

Abstract: A thermally balanced electronic circuit having an element mounted on a suitable support base, a heat-sink having a bottom portion contacting the element and at least one flange projecting from the bottom portion, and a stress-balancing insert positioned on the bottom portion of the heat-sink and at least partially coextensive with the element, said bottom portion of the heat sink being secured to the element and to the insert by means of an adhesive. The insert is of a material having a coefficient of thermal expansion (TCE), .alpha..sub.1, different from the TCE, .alpha..sub.2, of material of the heat sink. The TCE of the material of the insert may be intermediate the material of the TCE of the heat sink and the TCE, .alpha..sub.3, of the material of the element. Preferably, the TCE of the material of the insert approximately matches or is equal to the TCE of the material of the element. The element, the bottom portion of the heat-sink, the insert and the adhesive layers form a balanced "sandwich" structure.