摘要:
A first terminal (791) of a device-under-measurement (DUM) is connected to a buffer amplifier (758) and to the inverting input (747) of an operational amplifier (754). A second terminal (792) of the DUM is connected to a buffer amplifier (756) having its output (796) connected to the non-inverting input (746) of the operational amplifier (754). The non-inverting input is also connected to the output (793) of a signal generator (760). The second terminal (792) is also connected to ground (767) through a programmable load circuit (762). A circuit (779) creates a feedback loop from the DUM and the load circuit (762) to the operational amplifier (754) to enable the amplifier to maintain a predetermined voltage across the DUM and to isolate the amplifier from current flow from the load circuit (762). An oscilloscope (766) is connected across the outputs (727, 796) of the buffer amplifiers (758, 757) and a computer (764) controls the signal generator (760) in response to a signal from the oscilloscope and also controls the load (762) via a load control circuit (765).
摘要:
A circuit for diagnosing the state of a load (LD) comprises a DMOS transistor (DMOS1) interposed between a terminal (OUT) of the load (LD) and voltage comparator circuits (CDT) in order to limit the maximum voltage input to the comparators (CDT) to reduce the circuit area occupied by the comparators (CDT) and consequently the cost of the diagnosis circuit.
摘要:
Die Erfindung betrifft eine Eingangsschaltung für die Erfassung, Auswertung oder Weiterverarbeitung eines Stromsignals (IS) mit einem als Shunt die Stromeingangsanschlüsse (E1, E2) überbrückenden Meßwiderstand (RM), an dem das Stromsignal (IS) einen Spannungsabfall (U) hervorruft, der einer eingangsseitig sehr hochohmigen Verarbeitungsschaltung (V) zugeführt ist. Es soll eine einfach aufgebaute Eingangsschaltung geschaffen werden, die wahlweise Strom- und Spannungssignale aufnehmen kann. Hierzu ist in den Stromkreis zwischen den Meßwiderstand (RM) und die Verarbeitungsschaltung (V) ein erster Spannungsteilerwiderstand (R1) geschaltet. Ein zweiter Spannungsteilerwiderstand (R2) wird mit seinem ersten Ende an einem Spannungseingangsanschluß (E3) und mit seinem zweiten Ende zwischen dem Meßwiderstand (RM) und der Verarbeitungsschaltung (V) angeschlossen. Bei diesem Aufbau steht der Spannungseingangsanschluß (E3) alternativ zum Stromeingangsanschluß (E2) zusammen mit dem gemeinsamen Eingangsanschluß (E1) für Spannungssignale (US) zur Verfügung.
摘要:
Appareil de mesure de courants faibles à grande dynamique. L'appareil de mesure comprend en série un préamplificateur multigammes et un moyen d'amplification logarithmique et, en outre, un moyen de seuillage, un moyen d'alarme et un moyen de lecture. Le préamplificateur comprenant en série un premier amplificateur différentiel (48) recevant sur son entrée inverseuse le faible courant à mesurer et un second amplificateur (52), le premier amplificateur étant doté d'une chaîne de contre-réaction linéaire (50) à très haute impédance, le second d'une chaîne de contre-réaction linéaire (54) d'impédance beaucoup plus faible, un moyen (56, 58) de réglage du zéro et un moyen (60) de test du gain de l'appareil étant en outre prévus sur le premier amplificateur.
摘要:
An integrated circuit is presented. The integrated circuit may comprise a first terminal, a second terminal, a control terminal, a current monitor terminal, a power transistor coupled between the first terminal and the second terminal, and a replica transistor coupled between the first terminal and the current monitor terminal. The integrated circuit may be configured to control a current between the first terminal and the second terminal based on a control signal applied to the control terminal. The integrated circuit may be configured to provide, at the current monitor terminal, a current monitor signal indicative of a value of said current.
摘要:
A circuit may sense the differential voltage across two nodes that each have a non-zero common mode voltage. The circuit may have a positive input impedance that is imposed across the nodes. An impedance compensation circuit may generate a compensation current that is delivered to the nodes that substantially cancels the loading effect of the positive input impedance. The impedance compensation circuit may generate a negative input impedance that is imposed across the two nodes that is substantially the same as the positive input impedance. The impedance compensation circuit may instead be configured to deliver the compensation current to the nodes.
摘要:
Methods and apparatus are disclosed for measuring an electrical current, particularly an AC electrical current, for example to measure a frequency response of a transformer. In a disclosed arrangement, a connection is made of a current input terminal for receiving a current to be measured to an input terminal of a differential amplifier via a portion of a resistive network. The resistive network holds the current input terminal at a ground voltage and the two input terminals of the amplifier at a common finite voltage above the ground voltage. The amplifier provides as output a measure of the current to be measured.