为什么是Vgs> Vth 时 NMOS导通，而不是Vgb

elec_888

actually the channel is formed between source and drain .. what can affect the flow from source to drain is basically the gate voltage .. if your bulk and source are not at the same voltage or the bulk is not the most negative voltage of your circuit (in case of NMOS), you will have what is called the body effect which will affect your threshold voltage ..

hope the answer is clear ... this is due to what i understood from your post