This circuit was found in documentation from the 1970s. However, it can be implemented with modern transistors such as 2N2222 for Q1 and BF494 for Q2. The crystal depends on the desired frequency.
This current-limited variable power supply was found in 1977 book. The diodes are according to...
The Texas Instruments LM5178 Buck-boost controller is capable of operating in the 4.2 to 55 V (60...
This circuit compares the input voltages by providing an output according to the curve next to the...