[sdiy] the most simple semicon VCO ever built

[Paul Perry]

>> Yesterday I browsed through a 1970 something issue of the
>> "Funkschau" mag. I saw a simple VCO, one cap , one
>> npn one resistor. Obviously the transistor was working
>> in tunnel diode breakdown, thus creating negative
>> impedance characteristic.
>> 
this is the notorious 'negistor'.
AFAIK nothing a PUT can't do.
Problems being: high voltage requirement (15 or more usually) 
& need to select transistors (2N2222 used to be a favorite)

There is a 3 page article abt it at keeleynet
(WARNING don't read anything else there!!!)

paul perry melb aust