Indicated by Popular Electronics, in an edition of the 90's, this circuit seems doubtful because of the inductance used, which must be large.
This battery monitor circuit with the TLV379 low voltage operational amplifier was obtained in the...
We got this circuit from Radio Electronics from July 1990. The circuit mimics the sound of the red...
This configuration often addressed on this site is from a 2000 documentation. The circuit can be...