The led lamp low-grade why current sound
The 12 v power supply meet the led light have the cause of the current sound is due to your power supply is provided by the 50 hz ac, and 50 hz transformers, and loose core. If it is a high frequency switching power supply, or dc power supply, is listening to less than 50 hz hum.
You couldn't hear the sound of the single. Current should be the current instability caused by electric magnetic vibration. High-grade didn't work in a very stable power supply should be no broken (continuous waveform, basic), when low, the power output is lighter, and load lighter, leading to power cannot be stable and continuous work, appear discontinuous phenomenon. When the pulsation frequency into the region of the human ear can identify when they heard the sound. In general should be the power source design is not perfect, if you want to change, if you have a basic knowledge, from the perspective of the feedback loop.
1, if appear this kind of current sound, then you buy the desk lamp of more times. Inside the power module is not very good. 2, the better the desk lamp of all is the use of constant current power supply, ensure that the service life of the lamp is longer.
LED lamp, can use dc power supply, high frequency switching power supply, constant current drive power supply, can also use the 50 hz inductive step-down transformer rectifier power supply.
