This circuit uses two quad op-amps to form an eight LED audio level meter. The op-amp used in this particular circuit is the LM324. It is a popular IC and should be available from many parts stores.

The circuit was conventionally designed with eight LED audio level meter made out of two low power quad op-amps which utilizes LM324. Volume Unit – an entity equal to a decibel for expressing the ...

The LM3914 LED bar graph driver was an amazing chip back in the day. Along with the LM3915, its logarithmic cousin, these chips gave a modern look to projects, allowing dancing LEDs to stand in for a ...

The unbridled development of radio broadcasting in the 1920s and 1930s demonstrated the need to standardize audio equipment, studio-to-transmitter links, and methods for measuring static and dynamic ...