Yes, negative resistance is indeed a very neat topic. We've covered it in different ways a few times (check Advanced Search) but the first thread which comes to mind is here.
The extra links are always welcome. Thanks for posting them!
Here are some examples of reverse bias oscillators which use negative resistance to work. **broken link removed** electronics **broken link removed** Simplest_LED_Flasher_Circuit
thanks - exactly what I tested. In school we had tunnel diode
oscillators, but using a transistor as t-diode was completely
unknown to me. Surprise, surprise
Do ya have any other components in odd circuitry ?