This circuit activates a buzzer when the voltage applied to the input falls below a preset value in R1. The circuit is from an 80's American documentation.
This circuit was obtained from a 90s Radio Electronics. The integrated circuit used HAA11508 is not...
This article was written by A. Fanzeres in the 1970s. We kept the original text. With the circuit we...
We found this circuit in an English publication in 1991. The circuit can be assembled with...