A system for energizing an inductive load includes a voltage regulator for providing a constant voltage across the load until the current builds up to a particular value, and a current regulator which then takes over to provide a constant holding current at a lower value. The voltage regulator may include a closed loop for holding the voltage across the inductive load constant or may respond to a regulated voltage value to control a power stage for providing a constant voltage. The voltage across a sensing resistor in the power stage controls the crossover from the voltage regulation mode, to the current regulation mode and the current regulator automatically resets the reference to control the power stage to provide a constant current of a lower value through the load. The system can be used to supply current to coils of injector valves in a fuel injection system, and may include two power stages for supplying current to two banks of coils. The regulator system is switched from one power stage to the other during successive 180° rotary positions of the engine for both stages.

Voltage and current regulator with automatic switchover

Disclosed is an operational amplifier including an input differential amplifier stage and an output driver stage, with each of the input and output stages having pole compensating capacitance means therein for improving the gain-versus-frequency characteristic of the amplifier. The output pole compensating capacitance means is a high voltage MOS capacitor which splits two of the poles of the amplifier''s transfer function, broadbanding one of the poles and narrowbanding the other of the poles to improve the gain-versus-frequency characteristic of the amplifier. The input pole compensating capacitance means is a low voltage PN junction capacitor which relocates one of the poles of the amplifier''s transfer function to thereby further improve the gain-versus-frequency characteristic of the amplifier while at the same time minimizing the total monolithic integrated circuit die area required for the fabrication of the input and output pole compensating capacitance means.

Integrated circuit amplifier having an improved gain-versus-frequency characteristic

An amplifier for a capacitive load which includes a pair of high-voltage tube output circuits connected in a power output tube arrangement operating in push-pull for driving a capacitive load together with a feedback network connected between the Schmitt arrangement and a pair of transistors interconnected in a complementary difference amplifier circuit, the output of the complementary difference amplifier circuit connected to the driving tube of the power output tube arrangement to provide an amplifier output level having low distortion, positive DC centering and a high order of stability.

Amplifier for driving electrostatic loudspeakers

The present invention provides a preamplifier, by which it is possible to prevent influence of noise components when there are noise components in power line. There is provided a transformer having a primary winding with a center tap and a secondary winding on output side, and the primary winding of the transformer is connected between plates of two vacuum tubes for performing differential amplification, and positive voltage is applied on the center tap of the primary winding. A switch may be arranged in such manner that input signal and output signal can be separately set to balanced state or unbalanced state.

Vacuum tube differential preamplifier having a transformer with a center tap

1,028,383. Valve and transistor amplifying and gating circuits. RANK-BUSH-MURPHY Ltd. Oct. 29, 1964 [Oct. 29, 1963], No. 42622/63. Heading H3P, H3T and H3W. In a push-pull amplifier, more especially for feeding a reactive load 7, the cathode of each output valve 1, 2 is returned to ground via an un-bypassed resistor 8, 9, respectively, and negative feedback is applied by means of a tertiary winding 13 on the output transformer 5, which is connected, in series with resistor 12 and D.C. blocking capacitor 14, between the cathodes. The output stage is driven by means of a pair of transistors 21, 22 each of which has an individual un-bypassed emitter resistor 25, 26, respectively, the two emitters being connected together by a resistor and D.C. blocking capacitor in series. The arrangement may be switched off, either by opening the positive supply to the screen-grids of the output valves 1, 2 by means of a switch 39, or alternatively by applying a positive pulse via terminal 36 and capacitor 37 to the base of an auxiliary transistor 30. The collector potential of this transistor then goes negative, biasing the output valves 1, 2 to cut-off. In addition, diode 29 common to the emitter circuits of transistors 21, 22 and which is normally conductive, is biased non- conductive, the biases on the transistors 21, 22 then becoming such that these transistors are also cut off.

Electrical signal amplifier

Geraet zur Magnetaufzeichnung von Video-Signalen mit einem elektromagnetischen Aufzeichnungswandler, der mit der Sekundaerwicklung eines Ausgangsuebertragers eines Gegentaktverstaerkers verbunden ist

Baldwin John Lewis Edwin

Papers

Electrical signal amplifier

Geraet zur Magnetaufzeichnung von Video-Signalen mit einem elektromagnetischen Aufzeichnungswandler, der mit der Sekundaerwicklung eines Ausgangsuebertragers eines Gegentaktverstaerkers verbunden ist