Using LM3909 integrated circuits, this circuit was found in an American documentation from the 90's. The frequencies can be changed by changing the capacitors.
This well-designed bistable configuration is for educational purposes. We found it in the...
This low power bass booster is from the 1977 National Semiconductor Audio Handbook. The circuit is...
This circuit, well known to our readers, only has a slightly different schematic representation, as it was...