According to one embodiment, an active clamp circuit includes a first switch element, a first diode, a first resistance, a first control circuit and a second control circuit. The sand mold may be removed from the core box prior to drying the binder completely. Preferably, the array of cells constitutes a layer having a height of less than 100 \u03bcm perpendicular to the surface of the component. Safe operation of the compressor can be achieved without the need or monitoring temperature distortions in the sucked in air stream.