We found this simple circuit in December 1975 Radio Electronics magazine. The integrated circuit is the 4009 CMOS, and the circuit works in both TTL and CMOS depending on the power supply.
This circuit was obtained in a 1975 documentation. It is intended for old vehicles that still use...
This circuit uses a diode as a radiation sensor. The operational ones are old because the...
This circuit was found in the March 1999 issue of Electronics Now magazine. The meter is analog and...