Transistors
Transistors are just like Transformers. Only 5 letters difference.
Transistor Building Blocks
Basics
NPN and PNP
- NPN Never Points In
- PNP Points In
The emitter is always the errow.
It's all about the bass. The diode test will work whichever way the errows point to. (i.e. npn will conduct base to emitter, and base to collector, pnp will conduct emitter to base, and collector to base).
Tips/Techniques
Darlington Transistors have Internal Resistors
See also: (sziklai vs. darlington)
https://circuitcellar.com/resources/darlington-vs-sziklai-pair/
Never Trust Data Sheets Power Mosfet ratings
https://www.eevblog.com/forum/projects/50w-really/msg5449229/ Perhaps I should have a page just for traps in data sheets.
Measuring R(ds)ON of an N-FET with Two Meters
- https://forum.allaboutcircuits.com/threads/measuring-mosfets-rds-on.181819/
- http://web.archive.org/web/20220127031735/https://www.engineersgarage.com/testing-mosfet-part-16-17/
It's possible, but be aware of what voltage your meter outputs, what is required for conduction, and what resistance to expect.
Gate and Source on a JFET are 'sometimes' interchangeable
I was looking at this data sheet for a repair (nte312): https://www.digikey.com/en/htmldatasheets/production/5439610/0/0/1/nte312 And saw this note at the end. This is discussed in forums online. Stack exchange and eevblog...
Misc
- https://www.eevblog.com/forum/projects/why-transistor-vbe-drops-when-transistor-is-in-active-region-bc547-ibconstant/ Curve tracer question: Does Vbe change when Vce increases (on a BC547)? (Contrary to popular knowledge)
