Interesting... the article says that Mr Lilienfeld "is credited with the first patents on the field-effect transistor (1925)", but the transistor itself was not developed until 1947!And do not forget Julius Edgar Lilienfeld
Interesting... the article says that Mr Lilienfeld "is credited with the first patents on the field-effect transistor (1925)", but the transistor itself was not developed until 1947!And do not forget Julius Edgar Lilienfeld
The tricky bit is biasing it.Yup. That's what I meant by "tricky." Most of the time it seems like 100Ω is adequate to squelch the RF oscillations.
The article is worth a read, I would like to read up on his patent application when I get time.Interesting... the article says that Mr Lilienfeld "is credited with the first patents on the field-effect transistor (1925)", but the transistor itself was not developed until 1947!
No, for that you pretty much have to go by the drain current vs. gate voltage curves shown on the MOSFET data sheet, so that you can take the gate threshold voltage into account. Once you have an operating point established, then you might be able to roughly estimate the gain from gm. If the manufacturer doesn't provide that information, you're out of luck.For a BJT I can look at the data sheet and roughly estimate the gain I'm going to get using the listed beta range, but what about a FET? Say I want to approximately predict what my drain current will be when I have 5V on the gate, do I just use the transconductance like this: \(I_d=(5)g_m\) ?
Yes, it will, and that in turn will change the drain-to-source voltage of the MOSFET, and that will have some effect on the drain current (very similar to the Early Effect in BJTs), at least slightly.Ok, one more question. In the Id vs Vgs plot, it gives the value that Vds was at in the test. But wouldn't a changing Id cause the voltage drop to change across the resistance that's between the power source and the drain?
It wasn't until the basics of semiconductor physics was understood by Shockley and company at Bell labs (and Lilenfeld's patent expired) that a practical working device was developed.Interesting... the article says that Mr Lilienfeld "is credited with the first patents on the field-effect transistor (1925)", but the transistor itself was not developed until 1947!
by Duane Benson
by Duane Benson
by Aaron Carman