This circuit was found in American documentation from the 90's. The circuit applies to any operational. The power supply can be between 5 and 15 V depending on the operational.
The experimental musical instrument with the LM3909 is suggested by National Semiconductor in...
The circuit shown is from Motorola's 1990 Linear Databook. The operating circuit is not common today...
This circuit decodes a 1800 Hz tone used in communications. The circuit is from an American...