Help Identify These Transistors

Hi All,

Can anyone help identifying these transistors?

My tester identifies them as Darlingtons.

But what I'm after is their specs.

Can they be used for audio?


Happy New Year
Andy
 

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Forward bias the B-E junction from a PSU or battery with a 2k2 series limiting resistor and see what the B-E junction drops. If it is around 1.1v or higher then it's probably some kind of Darlington.
 
From what was said.
I see Vbe 1.15V and Beta 60.
Could that be a Darlington and the 60 from reverse Beta.
Reversing emitter and collector keep a PNP being a PNP, as well a NPN becomes a NPN. However, gain is much lower.
As can be checked on BJT Spice model
BF ( forward ) and BR ( reverse ).
 
A Darlington has only one junction between base and collector (the one of the first transistor), so if emitter and collector were reversed, you should see a much lower voltage.

I think the combination of VBE and hFE makes sense if the second transistor has a resistor between its base and emitter and the test current is only just too small to turn on the second transistor.
 
APT makes mosfets and IGBTs. From the gate side you can’t really tell the difference. You could try pushing about 10 amps thru one, (1 ohm resistor array, 12 volt battery) by applying +12 on the gate. If you drop more than half a volt or so across the drain/source (collector/emitter) it’s an IGBT. If it’s closer to half a volt, it’s a “high voltage” mosfet. If it’s a low voltage unit, it will be closer to a tenth. Short gate to source, and check it with a diode test backwards to see if it’s got antiparallel diode. Mosfets always do, IGBT’s sometimes.


As far as the original darlingtons are concerned, the base-emitter resistors leak enough current to affect the hfe readings. Data sheets will show very low gain at low current even if the intrinsic transistor gain is higher.