sigma

octave octave

Overview

1. Eight buttons control the resistance value connected to pins 2 and 6 of the 555 chip. When S8 is closed as shown in the figure, the resistance value connected to the circuit is 10K. Together with R10 and C4, it constitutes the charge and discharge parameters of the 555 multivibrator circuit.

2. At this time, pin 3 outputs a frequency, check it with an oscilloscope;

3. When only S1 is closed in the circuit, the resistance connected to the circuit is 2K+2K+2K+2K+2K+2K+1K+10K

4. The frequency generated at this time is approximately equal to the frequency of the musical scale Do; if S1 and S2 are closed at the same time, due to the circuit characteristics, only S2 will work. Based on this, you can be smart to design a device that can generate a sound by pressing two buttons at the same time. Polyphony effect circuit.

Design Files

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