This sound intensity meter was found in a 90s Elektor. The circuit uses an integrated device from the time that is not common today. The indicator is a milliammeter.
A sub temperature sensor circuit with the Norton LM3900 amplifier is shown in the figure. R3 has...
Found in Popular Electronics from the 90s, this circuit can be used in tachometers. The integrated...
This circuit was obtained from a Popular Electronics of 1994. The magazine no longer exists in its...