This circuit was found in an American publication from 1965. The circuit uses components from that time. No information was given about the excitation transformer. Observe the high input power.
We found this circuit in an old Popular Electronics. The circuit is experimental, driving an LED...
This circuit was suggested by Texas Instruments in a 1968 publication. The transistors are of the...
Suggested by the National Semiconductor in 1980s documentation, this circuit uses components from the...