This circuit is based on the light comparison of two LDR sensors. We found it in a 90s Popular Electronics. The transistor must be according to the indicator or load being driven.
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...