Current amplifier having a low input impedance
First Claim
1. A current amplifier having an input terminal and an output terminal for receiving and supplying an input current and an output current, respectively, comprising a first and a second transistor each having a bias terminal, a transfer terminal and a reference terminal, the reference terminals of the first and second transistors being interconnected via a first resistor,characterized in that, the bias terminal of the first transistor receives a voltage of a predetermined value, the transfer terminal of the first transistor is connected to the output terminal of the amplifier via a second resistor, the reference terminal of the first transistor constituting the input terminal of the amplifier, and the bias and transfer terminals of the second transistor being connected to the transfer terminal of the first transistor and to a positive power supply terminal, respectively.
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Accused Products
Abstract
A current amplifier A1 includes two transistors Q1 and Q2 whose emitters are interconnected via a resistor R1. The input of the current amplifier is constituted by the emitter of the first transistor Q1, whose collector is connected to the output terminal of the amplifier A1 via a second resistor R2, and to the first resistor R1 via the main current path of the second transistor Q2. The current amplifier A1 has a simple structure and a low input impedance, as well as an easily controllable gain.
36 Citations
5 Claims
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1. A current amplifier having an input terminal and an output terminal for receiving and supplying an input current and an output current, respectively, comprising a first and a second transistor each having a bias terminal, a transfer terminal and a reference terminal, the reference terminals of the first and second transistors being interconnected via a first resistor,
characterized in that, the bias terminal of the first transistor receives a voltage of a predetermined value, the transfer terminal of the first transistor is connected to the output terminal of the amplifier via a second resistor, the reference terminal of the first transistor constituting the input terminal of the amplifier, and the bias and transfer terminals of the second transistor being connected to the transfer terminal of the first transistor and to a positive power supply terminal, respectively.
- 3. A current amplifier having a first and a second input terminal for receiving a differential input current, and a first and a second output terminal for supplying a differential output current, said current amplifier comprising a first, a second, a third and a fourth transistor each having a bias terminal, a transfer terminal and a reference terminal, the reference terminals of the first and second transistors being interconnected via a first resistor, the reference terminals of the third and fourth transistors being interconnected via a second resistor, the bias terminals of the first and third transistors receiving a voltage of a predetermined value, the transfer terminals of the first and third transistors being respectively connected to the reference terminals of the fourth and second transistors, the transfer terminals of the fourth and second transistors being connected to the first and second output terminals of the amplifier via a third and a fourth resistor, respectively, the reference terminals of the first and third transistors constituting the first and second input terminals of the amplifier, and the bias and transfer terminals of the second and fourth transistors being connected to the transfer and bias terminals of the fourth and second transistors, respectively.
Specification