This circuit is suitable for calibrating old oscilloscopes. It was found in a 1980s documentation. It generates precise signals given by the crystal.
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...