device for the detection of the presence of dielectric properties or to prove a change in dielectric properties of bodies using a hochfrequenzspannungsquelle

摘要

1403720 Proximity detectors - temperature alarms FISONS Ltd 8 Nov 1972 [16 Nov 1971] 53030/71 Heading G1N [Also in Division G4] A capacitative detector for e.g. the upper limit of mercury in a thermometer uses an arrangement as in Specification 1196033 (shown herein enclosed in a dotted frame) having a sensing capacitor C1 in a balanced modulator circuit. In this case the circuit is fed with modulated A.F. ( 50v on a 200 kc carrier) giving rise to a pulsed output taken through a D.C. blocking capacitor C3 Suggested applications:- presence or absence of solid, liquid or gas, or changes in dielectric effect thereof to operate an alarm, control, counter or recording device. An arrangement for mounting a thermometer in a spring clip/capacitor similar to that of Specification 1196033, is described . Reference has been directed by the Controller To Specification 1196033.