3:46 AM
@Circuitfantasist "IV curve does not depend on time. So, ... I use the simplest AC signal generator - the mains voltage reduced by a step down transformer, ." - Yes, that is the second silly conceptual mistake I made about plotting the tunnel curve. Your hardware setup using a transformer and one manual turn potentiometer looks backward, and I wrongly thought that if I used a high frequency triangular DC sweep, and used my US\$300, 50MHz, 1GSs/s to watch the tunnel is slow motion, ...
I should see the electrons swimming inside the tunnel. It is only when I use the digital sig gen to create the 200 kHz triangle 0~0.8V sweep, then I suddenly realized that time is an independent variable. This why in the (deleted) CD comment/chat when I read about the Lancaster guy explaining the idea of "Appropriate Technology" then I understood your stupid looking mains 50Hz sine signal with one hand turn pot is most appropriate in our Galaxy, ...

4:45 AM
Now I am studying the ADC part of the PCF8591 ADC/DAC module. I am glad to see the reference voltage range and analog ground can be hardware programmed, to setup ***a differential Vt voltage range (0V ~ 0.8V) *** for powering the tunnel diode.

3 hours later…
7:18 AM
And the tricky part of the cct and wiring design is the Reference sweep voltage range and Analog ground.
Loading can be 100kΩ and 10k conversion rate. Everything looks OK. So I can start programming. The first function is to setAnalogOutputVoltage().

4 hours later…
11:02 AM
Interesting... I wonder if there is such a high speed scope to see the trajectory of the operating point during the jump...

11:25 AM
I guess we should ask the physics blokes: physics.stackexchange.com/search?q=tunnel+diode

9 hours later…
8:26 PM
There is an interesting question there - Differential resistance vs. R = V/I. I would prepare an answer for it...