This 4-tube counter was found in Radio Electronics magazine from December 1959. The circuit uses a coil as a sensor to detect the passage of metallic parts or magnets.
This electronic flash circuit was found in the March 1961 Radio Electronics magazine. The circuit...
Like the previous circuit, this is used in the analog part of the telephone lines. The same...
This circuit was found in documentation from the 90s, being indicated for use with tape recorders given...