The network power supply 220V50Hz is rectified and filtered directly from the bridge and then added to the switching power supply chip through a switching transformer. The chip switching tubes turn on and off at a frequency of 100 kilometers per second (kHz). As a result, the square wave added to the switching transformer is actually greater than 300 V at a frequency of 100 kHz. the desired square wave voltage is obtained on the secondary side of the switching transformer and is sent to the load after being rectified and filtered by the diode.
Advantages: large size, high heat generation (under large loads), low power conversion efficiencyDue to these drawbacks, many portable devices (e.g., chargers) use switching power suppliesAdvantages: well regulated frequency, small crackle range, high immunity to interferenceDue to this characteristic, transformer power supplies are commonly used for all types of audio and analog amplification circuits. Good DC characteristics can be obtained by simple rectification and filtering operations.
Transformer efficiency increases, less copper and iron, low frequency transformer efficiency is low, large size, more copper and iron, high price. Application differences: industrial frequency transformer is generally used to convert 220V or 110V high power to low power, for small appliances (such as soybean milk machine, gamma cap, stereo, etc.) power supply, a wide range of applications; high-frequency transformers are more common (eg, battery chargers, electronic brakes, switching power supply, color TV power supply, computer power supply, LCD driver and power supply, etc.), and used in many occasions.
In the traditional amplifier, used for interstate coupling audio transformer in addition to the function of converting the voltage, but also has the function of converting the impedance, which can not be used as a switching power supply and high-frequency transformer is a major drawback. Audio is also low frequency. In addition: almost all power transformers, regardless of model, are now low-frequency transformers. Utilize their strengths and avoid their weaknesses. He finds this useful. Related Issues For example, on average every week on TV and radio. The so-called low-frequency transformer is an ordinary power transformer used to convert 50 Hz AC voltage, such as substations.