Found in an English publication from the 1980s, this circuit can be built with equivalent transistors such as the BC549. The signal must be applied to an external amplifier.
The shunt type regulators are connected in parallel with the load, deflecting the current to...
This circuit was found on an 80's Ham Radio. The transistor admits equivalent. The circuit can...
This circuit has two response curves that depend on the position of the tone control switch. The...