From BJTs to MOSFETs

[LekTronix]

As someone returning to hobby electronics and buying some basic items for stock, I'm interested in opinions on MOSFET replacements for the venerable 2N3904 and 2N3906 (small signal, general purpose, roughly complementary, and cheap).

 

[audioguru]

A Mosfet needs from a few volts up to 10V on its gate to turn on. A 2N3904 or 2N3906 needs only 0.5V to 0.8V on its base to turn on.
I have use the small 2N7000 Mosfet but found that a less expensive 2N4401 ordinary transistor had less loss.

 

[Optikon]

As someone returning to hobby electronics and buying some basic items for stock, I'm interested in opinions on MOSFET replacements for the venerable 2N3904 and 2N3906 (small signal, general purpose, roughly complementary, and cheap).

As pointed out, the 2N7000 (or 2N7002) is a long time popular part. Other good series are TNxxxx & TPxxxx depending on voltage and current. You ought to also have on hand a handful of power MOSFETS N & P channel types for those 1 Amp or greater occasions. Most MOSFETS I have seen have turn on thresholds between 2-4 volts or 3-5 volts... but they all usually spec the lowest RDS(on) at high gate voltages...

 

[Nigel Goodwin]

As someone returning to hobby electronics and buying some basic items for stock, I'm interested in opinions on MOSFET replacements for the venerable 2N3904 and 2N3906 (small signal, general purpose, roughly complementary, and cheap).

My main thought is WHY would you want to try and replace bipolar transistors with FET's? - both have advantages and disadvantages, depending what you're doing. If you check commercially produced products you will find that FET's are EXTREMELY rare - I doubt if they approach even 1% of transistors used in domestic electronics?.

 

[LekTronix]

Thank you all for your suggestions.

Maybe my use of the word "replacement" may have been misleading. I don't intend to remove BJTs from my arsenal, just have the Mosfets available for me to use where they are appropriate.