Abstract: An induction heater having inner and outer chamber cylinders connected in an air tight manner to a base and cover with an inner chamber being formed within the inner chamber cylinder and an outer chamber being formed between the inner and outer chamber cylinders, a heat exchange core disposed in the inner chamber, and an induction heater coil disposed in the outer chamber extending around the inner chamber cylinder. A flow path is provided from a cool air inlet in the base, along the outer chamber, into the inner chamber and through the inner chamber and core to a heated air outlet in the base in a counterflow direction relative to the flow along the outer chamber. The heater is especially well suited for use in convective soldering and rework apparatus.

Abstract: An induction heater having inner and outer chamber cylinders connected in an air tight manner to a base and cover with an inner chamber being formed within the inner chamber cylinder and an outer chamber being formed between the inner and outer chamber cylinders, a heat exchange core disposed in the inner chamber, and an induction heater coil disposed in the outer chamber extending around the inner chamber cylinder. A flow path is provided from a cool air inlet in the base, along the outer chamber, into the inner chamber and through the inner chamber and core to a heated air outlet in the base in a counterflow direction relative to the flow along the outer chamber. The heater is especially well suited for use in convective soldering and rework apparatus.

Abstract: Electric heater assembly for use typically with hand-held soldering or desoldering devices includes an elongated resistance element formed from a thin flat metal foil having three connected areas of different resistance, the differing resistance being caused by the different widths of the areas. The first area, to which terminals are attached, is the widest and acts as a heat sink. The second area decreases in width to the first area and acts as a transition area between the first and third areas. The first and second areas include first and second separated portions for providing electrical current to the first area and returning it therefrom. The first area includes first and second strips respectively connected to the first and second portions of the second area. The strips extend adjacent a first side edge of the third area in a side-by-side relationship to the distal end of the resistance element and then back towards the second area to a position where they are connected to one another.

Abstract: A switching circuit is comprised of a triac in series with the electrical load across an AC power source. The triac commences to conduct only after a unidirectional, gate-controlled SCR is conducting. Conduction of the SCR drives the gate of the triac enabling conduction. In turn, the SCR is controlled by a circuit network which regulates the potential at the SCR gate and is responsive to an external device which may be a photodetector and movable shutter in combination with a light-emitting diode (LED). Load conduction commences in synchronism with the source voltage crossing of the reference axis in a selected direction. When the load is turned off, an integral cycle is provided.