This circuit was found in a 90s American publication. The same configuration appears in several places on this site, obtained from different sources. The lamps can be replaced by LEDs.
The sensors in this circuit are NTCs and PTCs that work in a differential way by directly...
We found this circuit in a 90's Radio Electronics. The circuit can still be easily assembled as all...
Found in a 90s Electronic Design, this circuit rectifies sinusoidal signals providing output as...