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 circuit turns a lamp on and off with alternate touches of a switch. Modern Darlingtons can be used....
This circuit with the CK722 was found in a Raytheon publication from the 60's. The relay is of the...
This circuit was found in Radio Electronics magazine from July 1960. The components used are...