How much do you know about these characteristics of transformers？

2026-05-19

How much do you know about these characteristics of transformers?

1、 What is the difference between high-frequency and low-frequency transformers?

In general, low-frequency transformers refer to "power frequency transformers" that operate at (50Hz) to change voltage. The iron core used in low-frequency transformers is usually made of high permeability silicon steel sheets.High frequency transformer refers to a transformer that operates at high frequencies and functions as a converter. Due to the high frequency of the magnetic field, eddy currents are generated in the silicon steel sheet (the small magnets in the silicon steel sheet cannot keep up with the conversion speed), so high-frequency transformers generally use "high-frequency ferrite" as the magnetic core.

The difference between high-frequency transformers and low-frequency transformers is that they operate at different frequencies, resulting in some differences in material selection. The working principle of low-frequency transformers and high-frequency transformers is the same. Regardless of the operating frequency, energy is transmitted through electromagnetic induction.

Due to the difference in frequency between high and low frequencies, high frequencies can only be used in circuits with high frequencies and excitation source frequencies that match the transformer frequency, while low frequencies are the opposite and cannot be mixed. Even high frequencies cannot be used if the frequencies do not match.

If a transformer transmits a certain amount of energy, operates at a high frequency, transmits energy multiple times within a certain period of time, and can transmit less energy each time, then the materials used in the transformer are less and the structural size is smaller. Therefore, a typical high-frequency transformer has fewer coil turns and can be made very small in size, while a low-frequency transformer has more coil turns.

At the same power, the high-frequency transformer will be much smaller than the low-frequency transformer, and in this case, the high-frequency transformer will only be about one tenth of the low-frequency transformer. This is because it is necessary to protect the low-frequency transformer, reduce the u value, and make it with silicon steel sheets, but the efficiency decreases, so it is necessary to increase the volume for heat dissipation.

2、 Why do amplifiers need to use toroidal transformers?

Nowadays, many electronic enthusiasts choose ring transformers when choosing audio amplifier transformers. The use of ring transformers in audio amplifiers is determined by the characteristics of audio amplifiers. Unlike other devices, the power consumption of audio amplifiers not only changes rapidly, but also varies greatly. This requires transformers to have strong instantaneous overload capacity and fast response speed, otherwise it is easy to form noise, incomplete sound, poor sound quality, etc. Circular transformers, due to their large capacity and almost zero delay response in direct coupling, can meet the characteristics of audio power supply in the same volume.

Advantages of using toroidal transformers in audio amplifiers:

High electrical efficiency, iron core with no air gap, and high stacking coefficient.
Small in size and lightweight, the circular transformer can reduce its weight by half compared to the laminated transformer.
The magnetic interference is small, and there is no air gap in the core of the toroidal transformer. The winding is evenly wound around the toroidal core, which results in low leakage magnetic flux and electromagnetic radiation.
The vibration noise is relatively small, and there is no air gap in the iron core to reduce the induced vibration noise of the iron core. The winding evenly and tightly wraps around the annular iron core, effectively reducing the "buzzing" sound caused by magnetostriction.
The low operating temperature is due to minimal iron loss and low temperature rise of the iron core. The winding has good heat dissipation on the iron core with lower temperature, resulting in low temperature rise of the transformer.
Easy to install, the toroidal transformer only has one central mounting screw, making it particularly easy to quickly install and disassemble in electronic devices.

3、 What is the use of isolation transformers?

The definition of an isolation transformer: A transformer with two or more independently separated coils can be called an isolation transformer because the primary and secondary are completely separated (isolated) and energy is transmitted through a magnetic field.

To understand why isolation transformers are used, first of all, we need to understand China's power supply system. When supplying low-voltage users, the power supply system generally adopts a three-phase four wire system, with the neutral wire grounded. In layman's terms, it is the wire that goes to residents' homes, with one being the phase wire (live wire) and the other being the neutral wire. It is on the same position as the earth. When the human body touches the hot bottom plate, it will cause current to pass through the human body and form a circuit with the earth, causing electric shock hazards.

If an isolation transformer is used, it will be safer because the primary and secondary exchange energy through a magnetic field without a physical hard connection. Even if the human body touches a charged object, the potential of the charged part will be low due to the fact that the human body is in the same position as the ground, which will not cause electric shock hazards. When using an isolation transformer, two points should be noted: first, the secondary ends of the transformer cannot be grounded; The second is that the human body cannot touch both secondary ends at the same time, otherwise there is still a risk of electric shock.

4、 Isolation Characteristics Description

Assuming that transformer T1 in the circuit is a 1:1 transformer, that is, when it is input with 220V AC voltage, its output voltage is also 220V. However, it should be noted that the 220V voltage output by the transformer refers to the voltage between the two ends of the secondary winding, that is, the voltage between terminals 3 and 4.

The voltage between any end of the secondary winding (such as terminal 3) and the ground terminal is 0V, because the output voltage of the secondary winding is not based on the ground as the reference terminal, but on the other end of the secondary winding as the reference point, and there is high insulation between the primary and secondary windings.

In this way, when standing on the ground and only touching one end of the secondary winding of transformer T1, there is no danger to life (never touch both ends of the secondary winding 3 and 4 at the same time). If one touches the phase wire end of the primary winding, they will be electrocuted. This is the isolation function of transformers.

5、 Isolation function of power transformer

In many electronic appliances, AC 220V is used as the power source. In order to ensure the personal safety of users during equipment use, the 220V AC power source needs to be isolated, and a power transformer is used in this case.

At the same time, the power transformer reduces the 220V AC voltage to a suitable voltage, as shown in Figure 4 below. T1 in the circuit is a power transformer with voltage reduction and isolation functions.

In troubleshooting, it is often necessary to touch the components or ground wires in the circuit while it is powered on. Adding a power transformer can prevent the risk of electric shock.

6、Summary

Characteristics of isolation transformer at the input end of AC power supply:

If the third harmonic and interference signals in the power grid are severe, using an isolation transformer can remove the third harmonic and reduce the interference signals.
The use of isolation transformers can generate new neutral lines, avoiding abnormal equipment operation caused by poor neutral lines in the power grid.
The current waveform distortion caused by nonlinear loads (such as third harmonic) can be isolated without polluting the power grid.

Characteristics of isolation transformer at the output end of AC power supply:

To prevent the current distortion of nonlinear loads from affecting the normal operation of AC power sources and causing pollution to the power grid, and to purify the power grid.
Sampling at the input of the isolation transformer ensures that the distortion of nonlinear load current does not affect the accuracy of sampling, resulting in a control signal that reflects the actual situation.
If the load is unbalanced, it does not affect the normal operation of the regulated power supply.
Eliminate high-frequency transient interference using DC/DC converters.

Common problems with low-frequency transformers:

CXWON Transformer takes the road of technological progress.

High-temperature faults in transformers are not simply caused by the heat resistance of materials; more than 80% of power supply abnormalities stem from heat accumulation resulting from defective heat dissipation structural designs.

Abnormalities and potential hazards that may arise from the overheating transformer

2026-07-28

To achieve precise voltage output throughout the entire life cycle of the transformer and prevent long-term parameter drift, the key does not lie in merely optimizing the winding resistance, but rather in reducing the iron core's magnetic hysteresis loss from all dimensions including materials, structure, design, and process. This is to stabilize the magnetic circuit operation state and lock in the long-term output accuracy.

Hysteresis loss in transformer directly affects the output accuracy.

2026-07-28

The power frequency low-frequency transformers, with their electromagnetic coupling buffering characteristics, magnetic circuit energy storage voltage stabilization capabilities, and electrical isolation protection advantages, inherently possess the ability to resist voltage fluctuations.

The anti-voltage fluctuation capability of the power frequency transformer ensures stable power supply

2026-07-28

In the design system of power frequency transformers, the number of turns in the windings is not merely a basic parameter for meeting the voltage ratio requirements. Instead, it is the sole core variable that can be adjusted in both directions to control copper loss and iron loss, thereby achieving the minimization of total loss.

The design of the number of windings directly affects the balance between copper and iron loss in the transformer

2026-07-17