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 is based on an integrated TIPL62 from Texas Instruments, uncommon today and an...
This circuit appears in other articles and suggestions for circuits in this section from other...
This circuit was obtained from an Electronic Design from the 90's. The circuit generates signals at a...