Which one is the correct symbol of enhancement type MOSFET?

To really check on what really is the correct symbol for what, you should refer to particular standards.

Below is what the IEEE 315-1975 standard (which can easily be accessible online if you look on Google) tells us, for an example...

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(the IEC label nearby also indicates that it's ubiquitous to IEC standards as well)

You can claim that this is old information, and it is (frankly, I'm surprised how they don't update this standard). However, it's the most recent document that we have on this.

So which one is right? Well... Technically they're all correct and it depends what standard you're following. The Sedra/Smith textbook is not wrong because it's showing a different type of transistor symbol that doesn't show too much bulk (or substrate) activity, except for Figure 5.19a, which shows the arrow pointing outward on the P-channel FET.


There is no right or wrong way. For a given type of FET there are many different symbols. When you make a book, you have to select a symbol and stick to it, sometimes it is a personal preference, or something the book author has learnt during his studies.

The symbols used by Boylestad seem to be more commonly used.