This circuit is from a Radio Electronics magazine from July 1979. It uses the well-known IC 7107, a liquid crystal exciter that became popular in circuits of this type at the time.
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...