2.2v to 5v

[Acetronics2]

Alain,

I just want to learn, nothing more.

If I use BC237 for T1, and apply 3V to J1 input, would that be good enough to trigger BC237?

Hi, Sayzer

with those schemes ... all Silicium low power transistors can fit !!! ( just respect hfe > 100 ... and Vce Max > ... 12v , of course )

if I remember BC 237 is a good equivalent to BC 547 ( I must have a bunch here ... bought in the 70's ! ) BC 307 will replace BC 557 ( care to the pinout ! )

those kind of transistors , 30 or 40 years ago, were called UNT and UPT ( Universal N and P Transistors ! ) showing a > 100 Hfe, 45 v Vce and 100 mA min Ic ... and Silicium technology !!! ( LOL )

you could use them for every low power - low frequ applications without any pain.

Alain

PS: Hi, Steve ... extra load is 10 mA ... a real feather !!! But only the P transistor has to be strongly saturated ... to keep its Vce sat as low as possible.