This negative resistance circuit was obtained from a 1969’s American documentation. It can be made from modern components. See the characteristic obtained.
We found this simple toy organ circuit in the February 1968 issue of Radio Electronics magazine. The...
In the figure we have a practical circuit for use with a magnetic transducer. The 20 M ohms...
This circuit was found in a Motorola documentation from the 70s. The components are from the time,...