re the neg resistance transistor
yes, negative resistance is at the heart of the circuit. I first come across the same in 1968, in an article in a magazine called 'Wireless World'. As is stands it is useful as a rough sawtooth osc, and it only takes about 2 minutes to construct.
The base, although unused here, can be used as a sync input, if the oscillator is used as one of a group in a toy organ. Each base, if driven from a lower, modulating frequency, causes all oscillators to synchronize with the mod frequency, or so it was said at the time of publication.
The transistor should be a silicon planar type, as ony these types will work, I think.
Thanks for the fast response by the way.
Cheers.