This longwave signal booster circuit was found in the 1995 Encyclopedia of Electronic Circuits Volume 5. Note the dimensions of the board. The transistor is a general-purpose transistor.
This power supply was originally created for the CB16760E (Loudness System) but can be used in any...
Found in 1980s Electronic Engineering, this circuit uses common phototransistors as sensors. The...
This simple, unregulated power supply with an approximate 6 V output voltage can supply currents up to...