[jhawk22]

I'm in the process of matching 2SC1815 and 2SA1015 for a dynalo.

I'm attempting to match with a circuit documented in the matching dynahi transitors thread in order to calculate hfe.


My question is has anyone attempted matching with a 9v battery? My readings will not stablize with the mA METER and vrb measurements. They drop and drop along with the voltage in the 9v battery.



Any suggestions?

 

[Pars]

Not sure, as I did mine with a bench supply. Even with a bench supply, the readings really never stabilize... you just get into a rhythm of an approximate amount of time that things LOOK like they're going to stabilize and try to take your measurements for each device at the same time (15-20 secs or so).

However, IIRC, the mA readings were climbing as the device heated up... sounds like yours are going the other way as the battery is depleted? Maybe get some new batteries, and put 2 or more in parallel? Maybe one of those lantern batteries? What value of Ic are you trying to do your measurments at, BTW?

I was doing mine with two meters... one reading Ic and the other reading Vr for a known value Rb resistor, so I didn't have to futz around with moving meters/leads.. just wait and take both readings at the same (kinda) time. And I had built a test fixture with SIP pins for the tranny, so it was down to plugging in one tranny after the other.

 

[jhawk22]

Ok I figured out the problem. Read the schematic for the tranny wrong. The data sheet is somewhat confusing and hard to tell if your looking at it from a top or bottom view.
For reference, I found this picture

Pars, now my mA is climbing as you stated.

 

[Pars]

Quote:

Originally Posted by jhawk22 Ok I figured out the problem. Read the schematic for the tranny wrong. The data sheet is somewhat confusing and hard to tell if your looking at it from a top or bottom view. For reference, I found this picture Pars, now my mA is climbing as you stated.

Oh yeah, did I forget to mention these are E-C-B, not E-B-C as most std. trannies are

At least you found it...