This Nixie pipe circuit was found in 1965 documentation. Note the high supply voltage. Appropriate transistors of the time were used.
This circuit was found in documentation from the 1980s. Transistors are general-purpose types like...
We found this filter in a Popular Electronics from 1993. The operational amplifier can be the 741....
This is the conventional application of the UCN4202 to control a 12 V stepper motor with current...