This circuit was found in Motorola documentation from 1969. The transistors are from that time. The pulses are 200 ns with 500 mA. Observe the high supply voltage.
We found this circuit in a Popular Electronics of the 90s. The circuit still uses light bulbs, but...
This circuit is from Linear Technology 2005 documentation. The circuit is based on company...
The integrated circuit used in this power supply is no longer very common in power supplies today....