Nixie Tube Music Visualizer

Step 4 Design: AC to DC

Now that there are seven different audio signals for both channels, each containing a different frequency band, they are all converted to a DC volume signal. A 100uF polarized capacitor removes the 6V DC bias on the audio signal. A small signal diode rectifies the signal, discarding all of the negative values. Finally, the signal is smoothed out by a 4.7uF capacitor in parallel with a 10K ohm resistor. A DC voltage of the recent average volume of the signal is the result.