This modulator amplifier for transmitters was found in a 1947 American book. The circuit uses an output with 4 tubes connected in parallel and in push-pull.
This charger for small batteries was obtained from the 1982 Radio Experimenter Handbook. The...
This shield can be used both to interface microcontroller circuits or TTTL. The resistor in series...
This circuit not only indicates when the battery is on but also when it is low. The circuit is...