An apparatus for measuring small currents in which the current is applied to an integrator. The integrator output is applied to a slope detecting means, preferably differentiator and the integrator output is reduced at intervals to zero.
A first grounded-emitter amplifier transistor is followed in direct coupled cascade by a second grounded-emitter amplifier transistor. The first grounded-emitter transistor has direct-coupled collector-to-base negative feedback to regulate its collector current to be proportional to applied input current. The direct-coupled feedback includes means to regulate the collector-to-base potential of said first transistor to be proportional to the logarithm of the applied input current. The collector c...
A current regulator circuit for providing a regulated, temperature compensated current to a load. The current regulator circuit includes a unity-gain amplifier stage having a feedback circuit connected thereto. The output of the unity-gain amplifier drives an emitter follower, which drives an output transistor. The collector of the output transistor is connected to the load. The feedback circuit includes a transistor having its emitter connected in series with a diode, which in turn is connected...
A current collector for pumps, filters, heater housings and the like, the collector comprising a length of conductive wire wound spirally into a sleeve or cone, the shaped length of wire being adapted for placement in an inlet or outlet port of a pump, filter, heater housing and the like with one end thereof connected by a connector to a grounded (earth) connection. The length of conductive wire can be a length of stainless steel wire.
A current limiter comprising a cryostat provided with a first insulating feedthrough for an inlet conductor and a second insulating feedthrough for an outlet conductor, and a conductor running from one feedthrough to the other inside the tank, said conductor being constituted at least in part by a superconducting material, the cryostat being filled with a fluid at a temperature which is low enough to maintain said material in the superconducting state, said portion made of superconducting materi...
A variable electrical current in a first winding on a magnetizable core produces a magnetomotive force in the core. A second core winding produces an opposing magnetomotive force digitally adjustable periodically by a third core winding, a pair of switches and a flip-flop coupled to a center tap for alternately closing such switches when triggered to opposite states. The flip-flop is triggered between opposite states when the third winding current reaches a particular magnitude. In each cycle, t...
A current detector comprises a primary current transformer (21) having a core made of silicon steel sheets and permalloy sheets overlapping each other, together with secondary current transformers (22) and (23) having cores made, respectively, of silicon steel and permalloy sheets. As a result, the detector exhibits linear current transformation throughout any current range, so that current detection errors are minimized.
A current probe is provided which comprises a handle and a ring of magnetisable material for positioning around an electrical conductor, the ring being split into two portions one being fixed relative to the handle and the other being slidable therewithin between a position in which the ring is closed and a position in which the ring is open. The line of split of the ring is at an angle from the line of sliding movement of the linearly slidable portion. Damping is provided to prevent the slidabl...
A current switch for use in digital-to-analog converters having high dynamic accuracy includes first and second electronic switches, the first of which connects either a constant-current source or a constant-current sink to an output terminal. The output terminal is connected to a low-pass filter. When the constant-current source is connected to the output terminal, the second switch connects the constant-current sink to a reference-voltage source. When the constant current sink is connected to ...
