An electronic transformer is a device that can transform voltage or current from one level to another. Its internal structure and working principle differ from traditional power transformers, but it has wide applications and can be found in many different types of electronic equipment. An electronic transformer mainly consists of a magnetic core and several coils. When a DC power supply is connected to one of the coils, this coil generates an electromagnetic field, causing a change in the magnetic flux through the core. This changing magnetic flux induces a potential difference in the core and generates a current in the other coil. Because resistance and inductance exist in the coils, this causes voltage and current to change between the two coils. By adjusting the number and position of the coil windings, the desired output voltage and current can be obtained.
A power transformer is a device that converts high voltage to low voltage (or vice versa) and is widely used in actual production. It can be classified into many categories based on its structure and application.
1. According to structural type, power transformers can be divided into oil-immersed transformers, dry-type transformers, gas-insulated transformers, and fully enclosed circulating water-cooled transformers, etc.
2. According to their uses, power transformers can be divided into power plant transformers, transmission transformers, distribution transformers, transformers for manufacturing, and transformers for special purposes.
3. There are even more classification methods depending on the standards of various countries and regions.
An electronic transformer, with an input of AC220V and an output of AC12V, can deliver power from 50W to 300W. It is a transformer circuit developed based on a high-frequency electronic ballast circuit. It offers stable operation, small size, and high power, overcoming the shortcomings of traditional steel sheet transformers, such as large size, bulkiness, and high cost. Depending on the driving method of the high-frequency switching transistor, it can be divided into self-excited and externally excited types. First, the AC power is rectified into DC power. Then, electronic components are used to construct a high-frequency oscillator to convert the DC power back into high-frequency AC power. The required voltage is then output through the switching transformer and further rectified to supply the electrical appliances. Switching power supplies have advantages such as small size, light weight, and low price, so they are widely used in various electrical appliances. An electronic transformer is essentially an unregulated switching power supply; it is actually a type of inverter.
In simple terms, the working principle of an electronic transformer is the principle of electromagnetic induction, which is the process of "moving electricity generates magnetism, and moving magnetism generates electricity." The functions of an electronic transformer include: 1) power transformers, rectifier transformers, inverter transformers, switching transformers, and pulse power transformers for voltage and power conversion; 2) broadband transformers, audio transformers, and intermediate frequency transformers for transmitting broadband, audio, and intermediate frequency power and signals; 3) pulse transformers, drive transformers, and trigger transformers for transmitting pulse, drive, and trigger signals; 4) isolation transformers for insulating the primary and secondary sides, and shielding transformers for shielding; 5) phase conversion transformers for converting single-phase to three-phase or three-phase to single-phase, and phase conversion transformers (phase shifters) for changing the output phase; 6) frequency multiplier or divider transformers for changing the output frequency; 7) transformers for changing the output frequency. 8) Matching transformers that match the impedance to the load impedance; 9) Voltage stabilizing transformers (including constant voltage transformers) or current stabilizing transformers that stabilize the output voltage or current, and voltage regulating transformers that regulate the output voltage; 10) Filtering inductors that filter AC and DC signals; 11) Electromagnetic interference filtering inductors that suppress electromagnetic interference, and noise filtering inductors that suppress noise; 12) Inductors that absorb surge current, and buffer inductors that slow down the rate of current change; 13) Energy storage inductors that store energy, and commutation inductors that facilitate semiconductor switching; 14) Magnetic switching inductors and transformers that function as switches; 15) Controllable inductors and saturable inductors that regulate inductance.
