Actually a sample of somebody screeching recorded with a laptop built-in mic, heavily edited and it just happened to sound like an electric hum at a low volume. Do with it as you wish
路燈/電動嗡嗡聲
聲道：2
類型：wav
lamp-buzz、street-lamp、humming、buzz、electrical、street、lamp、machine、drone、fridge、appliance、hum、electricity、electric、noise
燈的嗡嗡聲、路燈、低唱、蜂鳴器、電動、街、燈、機、無人駕駛飛機、冰箱、器具、哼、電力、電動、噪聲
資料來源：freesound ( https://freesound.org )