B-Tech Electronic Systems - Prototyped a 12 LED VU Meter for a project, Uses just 3x LM324 Quad Op-amp ICs a few resistors and a decoupling capacitor, it works surprisingly well for
![operational amplifier - Op amp LM324 as pre-amp to LM3915 LED VU Meter - Electrical Engineering Stack Exchange operational amplifier - Op amp LM324 as pre-amp to LM3915 LED VU Meter - Electrical Engineering Stack Exchange](https://i.stack.imgur.com/4zAJC.jpg)
operational amplifier - Op amp LM324 as pre-amp to LM3915 LED VU Meter - Electrical Engineering Stack Exchange
![operational amplifier - Op amp LM324 as pre-amp to LM3915 LED VU Meter - Electrical Engineering Stack Exchange operational amplifier - Op amp LM324 as pre-amp to LM3915 LED VU Meter - Electrical Engineering Stack Exchange](https://i.stack.imgur.com/yZ2qV.png)
operational amplifier - Op amp LM324 as pre-amp to LM3915 LED VU Meter - Electrical Engineering Stack Exchange
![I made this led volume meter circuit, and only the first led turns on, and it's very dim. I didn't have 1n4148 diodes, so I used 1n4007 diodes instead (they have similar I made this led volume meter circuit, and only the first led turns on, and it's very dim. I didn't have 1n4148 diodes, so I used 1n4007 diodes instead (they have similar](https://preview.redd.it/a77k40o7x9e91.jpg?width=640&crop=smart&auto=webp&s=58344891c1461e0cddfaa2c5c2d8a3277f4fafc9)