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SO the NTE102/103(a) complementary transistors are a bit more compact(both are cans but the a ones are smaller and thinner). But I've noticed that in particular, the NTE102 is much more prone to frying than the NTE102a. But for this transistor latch oscillator circuit: enter image description here

When I use the (a) transistors, it fails to oscillate. But it works fine as a sawtooth oscillator when I use the NTE102/103 regular can transistors. I really do wonder why this is. For amplifiers, the (a) work far better.

Mr X
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    Does anyone still make these? Or is this new old stock? (Hate to hear if you are destroying old, expensive stuff like this.) The [NTE102](http://www.nteinc.com/specs/100to199/pdf/nte102.pdf) shows \$150\:\text{mW}\$ max and the [NTE102A](http://www.nteinc.com/specs/100to199/pdf/nte102a.pdf) shows \$650\:\text{mW}\$ max. – jonk Jan 18 '19 at 22:02
  • @jonk: YES they do. That explains why NTE102's fry more easily. But I am befuddled about why the 102A/103A don't work with the latch oscillator circuits. – Mr X Jan 19 '19 at 02:25
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    What you have there is effectively just a PUJT (built from two BJTs.) I've had to carefully select pairs of BJTs to make one PUJT out of them. There are several parameters that are important (and not so easy to measure.) When they built PUJTs, they of course design them correctly to work. If interested, it's easy enough to use a Spice simulator to show how hard it is to match up the BJTs to get them to work right. Once you get the right params, they just work like a clock, though. Using discretes, it's better to add a little more to the puzzle so that any BJT can be used. Germanium? Not sure. – jonk Jan 19 '19 at 03:21
  • I now recall writing a little something about the subject [here](https://electronics.stackexchange.com/a/344346/38098). The difference in your schematic is that one of the BJTs is used in reverse-active mode. Not sure why that is. And perhaps I should think more about that at some point. – jonk Jan 19 '19 at 04:05

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