We found this circuit in the 1964 RCA transistors manual. The sensor may be a common LDR and the transistor BC558. The relay has an operating voltage according to the power supply.
This circuit uses a unijunction transistor in a different configuration to generate rectangular pulses at...
What this circuit does is generate a signal in a ladder pattern, containing steps in which the...
This circuit was suggested by General Electric / RCA in a 1980s documentation. The components are of...