What is Current Amplifier – its Features, Types, Working & Application

A Current Amplifier is an electronic device that increases the level of an electrical current. It is used to amplify a weak input signal and produce a stronger output signal with a larger current level.

Current amplifier are used in a variety of applications, such as in audio equipment, instrumentation, and control systems. They can be designed to operate over a wide range of frequencies and current levels, and can be configured with different types of input and output signals.

Current Amplifier & Its Types

Features of Current Amplifier

  • High gain
  • Low input impedance
  • High output impedance
  • Wide bandwidth
  • Low noise

Types of Current Amplifier

  • Transistor current amplifiers
  • Operational amplifiers (op-amps)
  • Differential amplifiers
  • Current shunt amplifiers
  • Current feedback amplifiers
  • Class A, B, and AB amplifiers

Transistor Current Amplifiers

These amplifiers use one or more transistors to increase the level of a current signal. They can be designed with either bipolar junction transistors (BJTs) or field-effect transistors (FETs).

Operational Amplifiers (Op-amps)

Op-amps are electronic circuits that can be used to amplify a variety of signals, including current. They consist of several transistors and other components, and are widely used in electronic circuits due to their high gain, low input and output impedance, and low distortion.

Differential Amplifiers

These amplifiers are designed to amplify the difference between two input currents, while rejecting any common-mode signals that are present in both inputs. They are commonly used in instrumentation applications.

Current Shunt Amplifiers

These amplifiers use a current shunt resistor to measure the current passing through a load, and then amplify the voltage across the shunt to produce a current signal that is proportional to the load current.

Current Feedback Amplifiers

These amplifiers use a feedback loop to control the amount of current flowing through the amplifier. They are typically used in high-speed applications where a low output impedance is required.

Class A, B, and AB Amplifiers

These amplifiers are commonly used in audio applications, and are designed to operate in a specific range of current levels. Class A amplifiers are biased to operate in the linear region, while Class B and AB amplifiers are biased to operate in the nonlinear region.

Working of Current Amplifier

A current amplifier is an electronic device that amplifies an input current signal and produces a higher output current signal. The input signal is applied to the base or gate of a transistor, which acts as an amplifier to control the flow of current through the circuit.

When the input signal is applied to the base of the transistor, it controls the flow of current between the collector and emitter terminals. The transistor amplifies the input signal and produces a higher output current that is proportional to the input current and the gain of the amplifier.

The gain of the current amplifier is determined by the characteristics of the transistor and the values of the resistors used in the circuit. By adjusting the values of these resistors, the gain of the amplifier can be increased or decreased to match the requirements of the application.

Gain of Current Amplifier

The gain of a current amplifier is a measure of the amplification factor, or the ratio of the output current to the input current. The gain can be controlled by adjusting the values of the components in the amplifier circuit, such as the resistors and capacitors.


  • Signal amplification
  • Instrumentation
  • Audio amplification
  • Power amplification
  • Communication systems
  • Medical equipment

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