This circuit was found in 1980s Radio Electronics. The circuit includes the power supply. The ICL8038 circuit was very common at the time in this type of application.
The circuit presented in the figure is an amplifier for stereo sources with the Maxim MAX9723...
In fact, this 1994 circuit uses a scale of LEDs to indicate the pulse rate applied to its input....
What differentiates this circuit from the previous one (CB15613E) is the non-need to use a...