Electronic heat meter

摘要

The invention relates to an electronic heat meter, which operates according to the dual-slope principle and has one PTC thermistor in each of the feed and return lines of a heating system (solution). After a preselected quantity of heat transfer medium has passed, a flow (flow-rate) meter emits a pulse which sets a memory, as a result of which an analog circuit and a clock-pulse generator are connected to the supply voltage. The clock-pulse generator is connected to a digital circuit which controls four electronic analog switches in the analog circuit, of which two are simultaneously controllable four-stage analog switches to which the reference resistors and PTC thermistors are connected. The analog circuit consists of an integrator, which can optionally be bridged by the electronic analog switch, and a downstream comparator. The great advantage of this circuit is the low power consumption and the elimination of the offset voltage adjustment (balancing).