This circuit was found in a 1966 EEE. What it does is it converts the logic levels of 0 V and +4 V into -6 V and +6 V. Some older type transistors can be replaced by modern equivalents.
Maxim MAX20056B 6 Channel High Brightness LED Controller Maxim Integrated makes available through...
We found this circuit in American documentation from the 1980s. Transistors can be of general use....
This circuit for car engine spot adjustment was found in an 80's Radio Electronics. The circuit...