Found in 1969 RCA documentation, this circuit maintains constant current in the filament of a lamp or in a heating element. The circuit makes use of period components.
The TDA2613 is the mono version of the TDA1521A and has pinouts compatible with an integrated...
This circuit from an old 1978 publication uses germanium transistors but can be implemented with...
This project shows how to use an SCR in a starter circuit for a common fluorescent lamp. The SCR...