Abstract: The invention relates to a solar box (1) with a connection box (2) and at least one extension module (3, 20), which can be operatively connected to the connection box (2) via a first and a second connector part (9, 10) of a standardized interface (8). The connection box includes a connection shaft (5), into which contacts (7) lead from a shaft wall (11). The contacts (7) and the standardized interface (9) are arranged on the same shaft side.

Abstract: A cavity resonator having temperature compensation which comprises a pot and a cover, which together enclose a cavity resonance volume. The pot comprises a first material, which has a first temperature expansion coefficient and the cover comprises a second material, which has a second temperature expansion coefficient. The second temperature expansion coefficient is greater than the first temperature expansion coefficient, and an expansion of the pot and a deformation of the cover results upon a temperature increase, which each independently and also together cause an enlargement of the cavity resonance volume. Simultaneously, the resonance frequency remains essentially constant.

Abstract: A cavity resonator (20) having temperature compensation which comprises a pot (21) and a cover (22), which together enclose a cavity resonance volume (V). The pot (21) comprises a first material, which has a first temperature expansion coefficient (?1) and the cover (22) comprises a second material, which has a second temperature expansion coefficient (?2). The second temperature expansion coefficient (?2) is greater than the first temperature expansion coefficient (?1), and an expansion of the pot (21) and a deformation of the cover (22) results upon a temperature increase, which each independently and also together cause an enlargement of the cavity resonance volume (V). Simultaneously, the resonance frequency remains essentially constant.

Abstract: An electro-optic welding lens assembly for use in a welder's helmet or a protective eyeshield and including at least one liquid crystal filter element adapted to be controlled with regard to its light transmission as well as control means for changing the rate of light transmision of the liquid crystal filter element. The control means comprises a first manually adjustable control circuit operating independently of the amount of light falling on the lens assembly and including means for adjusting the rate of light passing through the liquid crystal filter element. Further, there is provided a second automatically operated control circuit operating in relation to the amount of light falling on the lens assembly. The second control circuit operates only within a range of light intensity above a predetermined threshold value to limit the rate of transmission of light passing through the liquid crystal filter element.