Abstract: A device to compensate for the thermic effects of an external source on a sensitive element in a system for automatically controlling the temperature reached by foods in heated vessels. The device includes a conventional range and a potentiometer for controlling a gas or electric heating element. Two heat sensitive elements are employed, one sensing pan temperature, and the other sensing ambient temperature. Electric circuitry automatically adjusts the heating element to reduce the heat output as the ambient temperature rises, so that a more constant vessel temperature is achieved.

Abstract: The present invention relates to a defrosting device, for a refrigerator with a number of cooling compartments, which only supplies heat to the evaporator in the fresh food compartment when strictly necessary, that is, when fast defrosting is required, whereas it provides for natural defrosting as long as this is sufficient. In a first arrangement, fast defrosting is performed each cooling cycle but only for part of the time the compressor is off and only after a given temperature threshold has been exceeded by the evaporator in the fresh food compartment or by the freezer. In a second arrangement, fast defrosting is only performed for one out of "n" number of cycles. Both these arrangements provide for energy saving as compared with known technology besides improving fast freezing performance by reducing food freezing time again as compared with known technology.

Abstract: A circuit is described in which a triac is to be fired to allow voltage to be supplied to start a motor which powers the compressor of a refrigerator. In order that the triac is fired at zero-crossings of the voltage, the voltage is supplied to two comparators which are connected antiparallel with one another, and which are supplied with a reference voltage such that the voltage difference at the input terminals of each comparator represents the voltage at the triac terminals with no added d.c. component. The outputs of comparators supply a square-wave voltage with zero-crossings synchronized perfectly with those of the main voltage at the terminals of the triac. The square-wave voltages are passed via compacitors and diodes to a comparator which reserves a string of negative pulses synchronized with zero-crossings of the triac. If the comparator is gated by an IN signal indicating that the temperature is above a predetermined value, the pulses are fed via the transistor of the gate of the triac to fire it.