In the figure we have a stereo decoder from the 70's with pilot lamp for signal indication. The circuit employs a component of the time, which is uncommon today.
This circuit is suitable for SSB modulation and was obtained from an amateur radio documentation from...
This circuit was obtained in a 90’s Popular Electronics. The operators admit equivalents such as...
This 7400 TTL circuit has a memory, keeping the LED on when a pulse is detected. The circuit must be...