The following circuit is six LED stereo VU display diagram which build using Dot/Bar Display Driver IC LM3915. This VU disply should be connected before amplifier module circuit. You may connect this circuit at pre-amp output, tone control input/output or equaliser input/output.
The LM3915 is a monolithic integrated circuit that senses analog voltage levels and drives ten LEDs, LCDs or vacuum fluorescent displays, providing a logarithmic 3 dB/step analog display. One pin changes the display from a bar graph to a moving dot display. LED current drive is regulated and programmable, eliminating the need for current limiting resistors.
The LM3915′s 3 dB/step display is suited for signals with wide dynamic range, such as audio level, power, light intensity or vibration. Audio applications include average or peak level indicators, power meters and RF signal strength meters. Replacing conventional meters with an LED bar graph results in a faster responding, more rugged display with high visibility that retains the ease of interpretation of an analog display.
Download LM3915 datasheet