A direct-current converter has an electronic switch which can be made conductive by switch-on pulses and has current limiting by suppression of switch-on pulses. In order to make do with a low-loss current sensor which is easy to realize, a direct voltage corresponding to the peak value of the current is obtained with the aid of an additional switch, in phase with the electronic switch, which is preferably a reverse-operated field-effect transistor. The converter is particularly suitable for app...

The invention provides an electrical switch which reduces arcing by utilizing slidably mating members. In addition the switch provides large area gold contacts. Because of the above characteristics the invention provides a switch that can handle high and low current and allows dry current switching. In addition the inventive switch provides a switch which closes an alternative circuit to indicate that the normal circuit is open.

The invention relates to a d.c. to a.c. converter comprising two transistors (22, 25) and an output transformer (21). This converter also includes an auxiliary d.c. voltage source (43) and is provided with an auxiliary winding (40) of the transformer (21) which connects the base of one transistor (22) to the base of the other transistor (25). According to the invention, the combination of the auxiliary d.c. voltage source (43) and a control circuit of the two transistors (22, 25) comprises a cur...

A post type oil filled current transformer having a U-shaped primary winding formed of a tubular conductor. An oil flow controlling hollow tubular member is disposed within the primary conductor. The tubular oil flow controlling member is vertically oriented and spaced from the internal wall of the tubular primary winding to define inner and outer coaxial paths permitting a downward flow of cool oil in the inner path within the tubular member and an upward flow of heated oil in the outer path be...

A current subtractor circuit utilizing a current mirror amplifier (CMA) as the subtracting element. An operational amplifier converts the difference current to an output voltage proportional to this difference. The operational amplifier additionally may be utilized to equalize the voltage drop across the conduction paths of the transistors comprising the CMA and to maintain the CMA output transistor in its constant current region of operation.

Current mirror amplifiers, which exhibit greater current attenuation (or gain) than prior art current mirror amplifiers taking up the same area on a monolithic integrated circuit die, are described in which the base-emitter junctions of the mirroring transistors are dissimilar in profile.

The difference between the base potentials of a pair of transistors which are interconnected at their emitter electrodes and operated with different densities of current flow through their base-emitter junctions, is scaled up by a fixed ratio. The scaled-up potential is applied between the base electrodes of a pair of current divider transistors, the emitter electrodes of which are interconnected to receive input current, to fix the ratio of the currents flowing via their respective collector el...

A fault current limiter in which a resistor is inserted by a running arc. The arc is allowed to burn in a commutating unit until the current zero-crossing. Upon the passage through zero the arc is extinguished and the current is commutated to a shunt resistor. The commutating unit comprises a gap-formed nozzle, in which the arc is burning. The nozzle is defined by two nozzle halves of a material which gives off gas under the influence of the arc. Close to the nozzle inlet is a pressure accumulat...

A current regulator, preferably constructed in accordance with monolithic integrated technology, for high currents is proposed, whose output current (I) is a function of an input quantity (E). In this case the output current (I) is less in a range of the input quantity (E) different from a value of zero than the value given in this range by the functional relationship between the input quantity (E) and the output current (I).

An A. C. current monitor for the protection of such devices as appliances and machine tools with a high Q transformer whose primary winding is series connected to the load line being monitored. The transformer is coupled to an audible alarm by a half wave rectifier filter and a solid state bilateral switch. By suitable choice of RC constant of the filter, a "chirping" response is obtained for load line currents marginally above a predetermined value in order to indicate the amount of overcurrent...