This balance indicator for stereo amplifiers was found in an 80's Elektor. The components used are common. Zeners are 1.8 V or close to that value.
This circuit was found in a 2006 publication. It uses discrete components and CMOS that are still...
The sensor of this circuit is a common diode, and the measured range is from -10 to + 40º C. The...
The circuit presented was found in the Linear Applications Handbook of the National Semiconductor of 1994....