Audio level meter using UAA180 LED driver

Using the UAA180 integrated circuit , can be designed a very simple and low cost audio level meter electronic project , that can be used in various audio circuits .
The UAA180 IC is designed to drive 12 light emitting diodes (LEDs). As you can see in the circuit diagram , this audio level meter electronic project requires few external electronic parts . As you can see , this project use excepting the UAA180 IC some operational amplifiers IC , that forms (using some passive electronic components ) active filters for separation ( filtering ) audio signal that will be a reference for the UAA180 IC .

The UAA180 based audio level meter, must be powered from a dual 15 volts DC power supply circuit (15 volts for powering the UAA180 IC and a +/- 15 volts for powering active filters ) .
Components required for this electronic vu-meter are : R1=47Kohm, R2= 1Mohm, R3= 33Kohm, R4= 10Kohm,R5= 220ohm,R6-9=390ohm,R7=2.2K ohm,R8-10=330Kohm,R11=180Kohm, C1= 47uF 25V, C2-4=47nF 100V, C3=2.2uF 25V, D1-D8= LED GREEN , D9-10= LED YELLOW, D11-12= LED RED, D13....17= 1N4148, IC1= UAA180 , IC2= TL072 op amp.

The measurement of audio levels is showed with a scale where it is displayed by the use of a growing light band which is suitable for measuring approximate values.