Amplifier principle

Guide: Amplifier As the name suggests, it is a device used for amplification. The following small series will introduce you to the amplifier. The principle, children's shoes come to learn how it is magnified ~~~

Amplifier Principle -- Introduction

Amplifier is a device that increases the amplitude or power of a signal. It consists of tubes, transistors, and other components. Amplifiers are essential in automation and signal processing systems. Amplifier works by using an input signal to control an energy source, with the energy supply providing the necessary power for amplification. Linear amplifiers reproduce and enhance the input signal, while non-linear amplifiers produce outputs based on a functional relationship with the input.

2. Amplifier Principle - Power Amplifier

High-frequency power amplifier is a device that converts DC energy into high-frequency AC output. It is used in the final stage of transmitters to amplify modulated signals. Amplifier can be classified into three working states: A, B, and C, with most operating in Class C.

Class A amplifier has a current flow angle of 360 degrees and is suitable for low-power signal amplification.

The output stage of a power amplifier uses a large static current to ensure both halves of the signal are amplified linearly. If the signal is too strong, distortion may occur due to saturation or cutoff.

Class B amplifier has a current flow angle of about 180 degrees. It uses two transistors to amplify each half of the signal, which reduces distortion but can cause crossover distortion if not properly biased.

Class AB amplifier has a current flow angle between 180 and 360 degrees. A small bias current is added to reduce crossover distortion, making it more efficient than Class A.

Class C amplifier has a current flow angle less than 180 degrees. It is commonly used in RF applications where a tuned circuit filters out distortion, resulting in a clean output waveform.

3. Amplifier Principle - Operational Amplifier

An operational amplifier (op-amp) has two inputs: the inverting (-) and non-inverting (+), and one output. It amplifies the difference between the two input voltages. Op-amps are widely used in audio, filtering, and signal conditioning circuits.

If the voltage at the inverting terminal is higher than the common ground, the output voltage will be opposite in direction. Conversely, if the non-inverting terminal is higher, the output follows the same direction. This makes op-amps versatile for various configurations like inverting and non-inverting amplifiers.

Operational amplifier output is proportional to the difference between the two inputs. In audio systems, the formula is often expressed as: Output Voltage = A₀ × (E₁ - E₂), where A₀ is the open-loop gain, and E₁ and E₂ are the input voltages at the non-inverting and inverting terminals, respectively.

Expand reading:

1. In-depth understanding of the differential amplifier

2. These operational amplifiers Did you notice the knowledge?

3. Various amplifiers Comparison

Electronic tube