Re: tunnel diodes retrace lines in curve tracer


Ed Breya
 

You can actually trace the full TD curve, including the negative resistance region, with a special curve tracer or fixture. It's all about keeping the impedance levels very low. As I recall, there's a good example DIY one shown in the old GE Tunnel Diode manuals, from the 1960s. I even thought about making a TD fixture for the 576, but then I got back down to earth and considered why I would want to do that - other than just for the hell of it. I'd use a regular curve tracer really only to see if a TD is good, or to determine the peak and valley info on unidentifiable TDs, or sometimes to see if an unknown part is even a TD in the first place. All of these things can easily be determined without seeing any detail about the negative resistance region. The curve there is well known and predictable, so even if you don't see it, you can picture it. There is one area that could be an interesting use for a TD fixture, not just for them, but in designing low level negative resistance circuits, where you don't already know the expected shape of the curves.

Ed

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