This interesting circuit was found on the Internet and is based on the 555. The circuit uses power MOSFETs that determine its output. No information about the transformer was provided.
The circuit shown is based on the LM101A; diodes can be replaced with equivalents. Resistor R1...
With the disappearance of the light falling on the LDR, the relay closes its contacts by...
We find this circuit in an American 1980s documentation. Modern equivalent integrated circuits can be...