This circuit is from a 1964 Electronic Design. The transistors are from that time. They can be replaced by current equivalents.
This circuit is from an Electronics Now from the 90s. The circuit uses a power integrated circuit...
We found this circuit in GE's 1977 transistors manual. Transistors admit equivalents according to the...
This circuit consists of a relaxation oscillator that generates high voltage pulses in a flyback...