Thank you for your quick response.
I thought it was a resistance because it is labeled "R" and not "F".
I found this scheme on this link:
www.instructables.com/id/Analog-IN-13-ba...ie-tube-thermometer/
But there are discrepancies with the transistors (see BeerLogic discussion on this link) and the type / value of the inductor "L1" is not specified.
What scheme do you suggest for the replica? Does the scheme already exist for -20º to + 40º?
Mr Nixie: “The termometer has a second input, but actual the circuity isn't able to display temperatures lower than 2 ° C. The measurement range of this input is actual + 30 ° ... + 60 ° C and can be used e.g. to monitor the processor temperature of the PC. But I can do a redesign for an extended temperature range on the second input, displayed on the left scale, let's say -20 ° ... + 40 ° C ”