Abstract: A method of controlling the supply of power to electrical loads with a minimum of switching surges in which the loads are each electrically subdivided into at least two equal subloads. The subloads of each load can be connected each time arbitrarily in at least three main power stages to an A.C. mains. In order to obtain a minimum switching surge effect on the A.C. mains while providing finer power control six additional intermediate power stages are provided, in which starting from one of the three main power stages, the subloads are switched in a continuously repeated cycle of six A.C. half waves in the first intermediate power stages during the third and sixth half waves in each cycle and in the second intermediate power stages additionally during the second and fifth half waves each time to the next lower main power stage, which in the case of a series arrangement is that in which the power consumption is switched off.

Abstract: A method of controlling several clocked loads controllable individually and independently of each other, more particularly heating loads of an electric oven, for minimizing the demand on an alternating current mains due to switching transients. More particularly, the loads are energized in sequence to prevent flickering when the loads are coupled to a common phase of the alternating current mains are switched on each time at the beginning of their clock period. The clock periods of the various loads are of equal length. All loads neither switched off nor switched to full power in a switching cycle are connected to the mains so as to be interlinked in time in a manner such that, when the preceding load is switched off, the next load is switched on. Such a switching cycle is started again each time at the beginning of a common clock period independently of the length of the switching cycle.

Abstract: Cooker automatically controlling the heating process when bringing a food material to the boil on an electric hotplate and preventing it from boiling over at the end of the heating process. At the beginning of the heating process the power supplied to an electric hotplate can be set to a constant value which can be selected. A microprocessor continuously determines the rise in the temperature of the base of the pan as a function of time. At a pan-base temperature above about 70.degree. C. the actual value of the rise in temperature is compared with a present desired value and when deviations occur the heating power is switched over so as to approximate the actual value of the rise in temperature to the desired value. At a pan-base temperature above about 90.degree. C. a bending point in the temperature rise of the pan base is reached after which the heating power is switched off.

Abstract: A solar collector comprising a U-shaped absorber sealed in an evacuated cover tube provided with a semi-cylindrical reflector on its inner surface, the U-shaped absorber being arranged between the cover tube axis and the reflector, with the central plane of the U-shaped absorber including the center lines of its legs and coinciding with the symmetry plane of the reflector.