5 LED VU meter circuit diagram using KA2284

This is a simple circuit diagram of 5-LED audio VU meter using IC KA2284/KA2285. The KA2284, KA2285 are monolithic integrated circuit. It is a logarithmic display driver IC. And it is Bar type display driver using 5-Dot LED. The KA2284/KA2285 has a wide range supply voltage capacity of 3.5V-16V, but we recommend to use about a 12VDC power supply.

Circuit Diagram:

Fig: 5-LED Dot/Bar (VU meter) circuit diagram

LED Sound level display circuit by using IC LM3915

This circuit is about audio sound level LED display, indicator, monitor or you can say it “Audio VU (Volume Unite) Meter”.
This is a simple audio sound level LED display circuit diagram. The circuit is completely  based on  a single ic LM3915 from National Semiconductor. The LM3915 is a monolithic integrated circuit. It displays the audio sound level in terms of 10 LEDs and providing a logarithmic 3 dB/step analog display.

Audio sound level display circuit diagram

Fig: Circuit diagram of sound level display using ic LM3915

The audio sound level LED display circuit can operate from a single supply 3V to 25V. But I  suggest to use 9-12V. LED brightness can be controlled with a single pot( variable resistor) as shown 10K ohm in the circuit. Connect the audio input signal in Pin-5 of LM3915 from output of a audio device like output of audio amplifier or any other source.

The Pin-9 of LM3915 is to select dot or bar mode display. To make the circuit moving dot display instead of a bar graph display disconnect the Pin-9 from +V.