We found this circuit in the old Mullard transistor reference manual from 1960. The circuit is powered by a single battery and the transistors are germanium common at the time.
The given number circuit is used to activate the relay by interrupting the light beam that hits...
With this circuit you can control up to 3 A of LEDs in different sequences, using a PWM...
No information is given on the transformer in this circuit that we found in an American 1967...