This version of triac control is from a 1968 documentation. The circuit uses components from the era that can be replaced with modern equivalents.
This circuit provides a constant current of 1 mA, stabilized by an LED, which can be equivalent to that...
This receiver for the mid-wave band was found in a documentation from the 60's. The transistors are made...
This circuit converts a positive CMOS supply voltage to a negative one. We found it in a 90s...