You must have a capacitance meter which able to measure in picofarads.
actually, I'm lucky to have one I use for my speaker projects 🙄
will look at it tomorrow
thanks!
capacitance figures seems quite high
fluctuates on the pf setting
nf setting gives stable readings
testing Hfe with multimeter appear to give correct readings, around 40
but I need a more stable way to connect transistor to meter
maybe just solder small wire bits to the legs for easy plug in
hmm, a sil/dil socket, or something
fluctuates on the pf setting
nf setting gives stable readings
testing Hfe with multimeter appear to give correct readings, around 40
but I need a more stable way to connect transistor to meter
maybe just solder small wire bits to the legs for easy plug in
hmm, a sil/dil socket, or something

Back in the old days you had to open a semiconductor book to look at a datasheet, instead of clicking a pdf.
Of course, the semiconductor data book comes free if you've got a relative employed at the Philips NatLab in Eindhoven.
Free online datasheets often are abbreviated versions, sometimes saves you 10 to 14 pages.
A bunch of BD139/140s in parallel make a fantastic class A headphone amp output stage.
Philips versions are much nicer, Cob of 5.7pF, downside that the power they handle is 2/3d of the different die version.
Does anyone have a couple of genuine Philips BD139-16 and BD140-16 pairs for sale?
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