3904/3906 tranny specs

[be053520]

Rob wrote:


>Since I am using the transistors as switches, I wouldnt think Vbe=Vc as
>being a problem.
>
>let me know..
>Rob


No, not really...
But I've experienced another nasty thing about trannies as a switch.
The transistor was used in a voltage-shifter circuit and I had to connect a
square-generator (about 1Hz) to it.
I started the generator and left it alone for about half an hour.
When I came back the tranny was broken.
When I compared load-line and transistor-curve (ofcourse after the usual
cursing and wishing all trannies to hell :-))it seems to be that the
Vbe-capacitor (specific to every tranny) was the cause.
The transistor has switched to slow (the cap slowed it down) between on and
off-state, became hot and broke down...

Never got this problem before...

Strange huh, any other explainations?

bye

Tom Verheyden.