nMOS symbol in transceivers, etc.

Hi All,

I would like to ask a question on nMOS transistor in TI transceivers & Multiplexer/Demultiplexer.

For a bipolar junction transistor, either NPN or PNP, one can readily recognize the different terminals (emitter, base, collector) from the schematic symbol.



However, in the following nMOS transistor symbols I saw in several TI documents, it seems that the symbol itself is symmetric with respect to two of its terminals. I have no knowledge of nMOS transistors so I would like to ask a question: does this mean that they are symmetric, or actually they are asymmetric? Can current take only one direction (same as poles’, opposite with electrons’), or it can flow in both directions?









Sincerely,
Zheng