Published by Philips in 1965 documentation, the sensor for this circuit is a common LDR. The transistors are general-purpose types from the time, only TR3 is a power type according to the load.
The existence of field effect transistors at the input of the integrated circuit (operational...
This circuit has a maximum output current of 5 A, and the 2N3055 must have an excellent heat sink....
This circuit is suggested by Motorola and is based on a 1723 voltage regulator. The 2N3055...