We found this circuit in an old Popular Electronics. The circuit is experimental, driving an LED from signals applied to the LDRs. The power supply does not have to be symmetrical.
This speed or priority switch set uses two LED indicators and two SCRs in a common configuration. The...
Found in a 90s American documentation, this circuit is used in vehicles with contact breaker. The...
This circuit for activating a relay was found in a Radio Electronics magazine from August 1962. The...