This circuit is from an 80's publication. It makes use of small 6 V x 50 mA incandescent lamps. The diodes can be general purpose or even 1N4002. The transformer is 6.3 V with 100 mA or more current.
This circuit is from a PopularElectronics of June 1992. The magazine no longer exists, but the...
The sensor of this circuit is a common diode, and the measured range is from -10 to + 40º C. The...
The author has many books he had written in Eglish (See the Biography) published by famous...