LED driver (CB20550E)

Found in the documentation on PCs, this circuit excites LEDs whose current is determined by R3.

MRF1K50H 1500W Power RF Transistor (COM047E)
It can be obtained from Mouser Electronics the new 1,500 W RF high power transistor MRF1K50H fro m...
Transistor Identifier and Tester (CB3901E)
This circuit was found in an old American documentation. The transformer is of the type found in...
UJT Electronic Organ (CB1435E)
We find this simple musical instrument in a 1977 Radio Shack documentation. The key resistors must be...