Abstract: A detector circuit is to be used for measuring current by means of substantially identically wound ring core transformers, in which magnetomotive forces are induced by a main current. The magnetomotive forces are counteracted by magnetomotive forces induced by a compensating current. Two of the ring core transformers (2, 3) are magnetized in antiphase by means of a modulation signal. The detector circuit includes optionally a synchronous rectifier for providing an adjusting signal for the compensating current. According to the invention means are provided for compensating for possible differences between the two ring core transformers for the modulation signal. These means include a common winding surrounding the two ring cores (2, 3), said common winding detecting a possible error signal used in a negative feedback loop which automatically seeks to establish an equilibrium.

Abstract: A power change mechanism for variable power riflescopes includes a resilient member disposed between the riflescope housing and the power change ring for automatically rotating the power change ring from one power setting to another upon activation of a latch mechanism. The automatic power change mechanism may include apparatus for overriding such automatic capabilities in order to provide for manual power change.

Abstract: The invention relates to a radiator valve assembly which includes the well known adjustable throttle valve and seat therefor in combination with an insert in the downstream side thereof which has a fixed throttle passage extending axially thereof. The throttle passage has a cross section which converges on the inlet side thereof and is sufficiently long to minimize the developing of turbulence in the flow stream.

Abstract: The invention relates to a method of removing air or gas bubbles tending to collect in the "dead space" of a piston burette or another liquid dosage piston pump during operation thereof. The venting is performed by sucking a substantial volume of air into the pump cylinder in addition to a certain amount of liquid, and the air and part of the liquid within the pump cylinder is thereafter discharged therefrom. A piston dosage pump for carrying out this method comprises a valve mechanism by means of which the pump cylinder may be selectively communicated not only with a liquid inlet conduit and a liquid outlet conduit, but also with an air inlet passage.