Aberration Questions

[joelorigo]

I ordered some MP38A transistors from a seller in Ukraine and also got a TC-1. My 10 MP38As measure 67-90, so right in the zone for what is on the build doc (hFE 79).

I don't have any BC107B transistors that are also on the doc, but I have various other ones. The BC107Bs on the build doc measure hFE 312 and hFE 318. I have 2 BC183s that measure 321 & 401. I have 2 BC108Bs that measure 230 & 420. I have a bunch of PN2222As that are around 190 and 2 BC183Ls that are around 200. Is the goal to get transistors as close as possible to what is on the build doc? How will the higher and lower hfe of what I have will effect the circuit?

Also, below is a photo of a MP38A I tested on the TC-1. Is "ICEO" the leakage?

And I find that if I leave the transistor in, even the silicon ones, the readings go lower over time. For example the one from the photo below is saying hfe of 76 now, about 10 minutes after the phot was taken. This is normal?

 

[Cybercow]

I ordered some MP38A transistors from a seller in Ukraine and also got a TC-1. My 10 MP38As measure 67-90, so right in the zone for what is on the build doc (hFE 79).

I don't have any BC107B transistors that are also on the doc, but I have various other ones. The BC107Bs on the build doc measure hFE 312 and hFE 318. I have 2 BC183s that measure 321 & 401. I have 2 BC108Bs that measure 230 & 420. I have a bunch of PN2222As that are around 190 and 2 BC183Ls that are around 200. Is the goal to get transistors as close as possible to what is on the build doc? How will the higher and lower hfe of what I have will effect the circuit?

Also, below is a photo of a MP38A I tested on the TC-1. Is "ICEO" the leakage?

And I find that if I leave the transistor in, even the silicon ones, the readings go lower over time. For example the one from the pho below is saying hfe of 76 now, about 10 minutes after the phot was taken. This is normal?

Yes. Iceo = leakage from collector to emitter with base open.

 

[joelorigo]

Yes. Iceo = leakage from collector to emitter with base open.

I see, so it's actually "LCEO" not "ICEO."

 

[Cybercow]

I see, so it's actually "LCEO" not "ICEO."

No. ICBO is the current that flows across collector base junction under reverse bias condition with emitter lead open. Another transistor leakage current is ICEO (Where, I stands for current, CE stand for collector emitter terminal and O tells us that base terminal is open).

 

[joelorigo]

Okay thanks for that information.