We found this measurement circuit with a logarithmic scale in an Electronics Now from November 1995. The circuit uses an integrated component from that time.
This circuit was obtained in a Radio Electronics of the 90s. The circuit uses an integrated circuit...
This is the traditional configuration of na Astable Multivibrator using two NPN ttransistor....
Found in the 1995 Encyclopedia of Electronic Circuits volume 5, this circuit has a constant...