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How to reduce the electromagnetic interference of transformers on amplifiers?

2024-04-09

How to reduce the electromagnetic interference of transformers on amplifiers?

Reducing the electromagnetic interference of transformers on amplifiers is a complex but important issue, which can be effectively achieved through the following methods:

  1. Shielding technology: This is a key measure to reduce electromagnetic interference. For electric field shielding, shielded cables with metal sheaths can be used as input lines for the amplifier's input stage. When interference requirements are high, the entire amplifier, especially the input stage, can even be placed inside an electric field shielding box, ensuring that the shielding box is grounded. For magnetic field shielding, whether the shielding box is grounded does not affect the effectiveness of magnetic field shielding, but grounding can provide both electric field and magnetic field shielding effects.
  2. Transformer isolation: Due to the presence of numerous harmonics and high-frequency interference signals in the AC power grid, isolation transformers can be used to suppress interference from the AC power supply for amplifying circuits powered by AC sources. The magnetic saturation and hysteresis characteristics of the transformer magnetic circuit can effectively suppress these interference signals. In high-demand situations, a shielding layer, such as a thicker copper sheet, can be added between the transformer windings and grounded to further suppress interference.
  3. Selection of magnetic shielding materials: Choosing appropriate magnetic shielding materials such as soft iron, nickel-iron, ferrite, etc., can effectively reduce electromagnetic interference from transformers. These materials can absorb energy from the electromagnetic field, thereby reducing the intensity of electromagnetic interference.
  4. Hardware design optimization: During the hardware design phase of electronic transformers, reasonable design of the circuit board layout to reduce the distance between signal lines and power lines, and using appropriate laminates and electromagnetic shielding covers can reduce electromagnetic radiation.
  5. Loop filtering technology: Utilizing the characteristics of filters to filter the input and output loops of electronic transformers can effectively suppress electromagnetic interference. These filters can eliminate high-frequency signal interference.
  6. Grounding and shielding technology: Proper grounding can direct interference signals from electromagnetic radiation circuits into the ground, reducing interference to surrounding equipment. At the same time, reasonably setting up shielding covers and shielding plates is also an effective means to reduce electromagnetic interference.

In summary, reducing transformer electromagnetic interference on amplifiers requires comprehensive consideration of various factors and adopting multiple technical measures for comprehensive suppression. In practical applications, suitable methods or combinations of various methods can be selected for optimization based on specific situations.

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