Re: TM50X transistors


On Wed, 28 Dec 2011 20:45:45 -0000, "Christian"
<christian.servais@...> wrote:

I looked into this a couple of months ago and concluded that the BD809
(NPN), BD820 (PNP), MJE2955T (PNP), MJE3055T (NPN), TIP33C (NPN), and
TIP34C (PNP) would be readily available acceptable substitutes in
roughly that order.

Just be careful of the pinouts. The Tektronix TO-127 parts are ECB
while the TO-220AB and TO-247 parts listed above are BCE.
What about BD911/BD912 selected for a minimum Hfe higher than the
datasheet minimum? I used them without problem if I remember well.
My list is not exhaustive. :)

I probably did not include them because STM's web site blows. BD909
through BD912 should work fine but they have the same TO-220AB pinout
difference. I will add them to my list.

The things I would watch for are high Ft or hfe causing oscillation,
low hfe requiring excessive drive, and high leakage causing thermal

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