Found in a 1970 EEE, this circuit uses general-purpose transistors of the time. Transistors support equivalents and the ramp time ranges from 0.1 seconds to a few seconds, depending on C1.
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....