What is the purpose of the capacitor in a music synth circuit ?

I know how the capacitor works but i don't get the point of it. What i'm trying to ask is how does it help the circuit run current.

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iceng6 years ago
Can you show the circuit, please ? A
Gypsy-Love iceng8 months ago

feast your eyes on this beauty, such a great SCHM for this convo.

gmoon6 years ago
OK, so you know how a capacitor works. Good, that's a start.

As one of the fundamental building electronic blocks, capacitors can be used in many ways in a synthesizer:

-- In an oscillator, the part that creates the basic waveform (sound).
-- In a filter, that can modify that wave.
-- As "coupling capacitors" that allow an AC wave (sound) to pass through while blocking the DC offset that's often present after an amplification stage.
-- As "decoupling capacitors" that prevent unwanted AC (noise, HiFreq oscillations) from passing through to the next stage.
-- As power filter capacitors that help convert the line voltage into something smooth and useful (DC voltage).

That's just a few uses. In almost all these case, capacitors work together with other electronic components (resistors, inductors, transformers, transistors, etc.) to do the job.
Good answer.
PKM6 years ago
Imagine an automatic flush toilet. The tank fills with water until it's full, at which point it flushes and empties, and start refilling. If you replaced that tank with a coffee cup, it would flush a lot more often; if you replaced it with a rain barrel it would go for a long time between flushes.

A simple audio synth is like this- the capacitor is effectively an electric "tank" that fills up until it's full, empties, and refills. The filling and emptying happens a few thousand times every second and that is what produces the output signal. A bigger capacitor will take longer to fill, so will fill and emnpty less often, so the output wave will have a lower frequency. The resistor also affects the frequency- if you restrict the flow of water/electricity the tank will take longer to fill each time and so again the frequency if it filling and emptying will be lower.

The capacitor in a high-power audio amplifier, on the other hand, is just a reservoir of electricity to help the power supply provide a lot of power in a short time when your 120W subwoofer kicks.
acidbass6 years ago
well it really depends on what circuit you are talking about and what synth system you are talking about

now in an attempt to help you here is my understanding

I own one synth system (i am a dj) and i am not the most electronics saavy guy but my understanding of the capacitor being there is because it is used more so as a storage center so the system does not draw so much power also the system produces sound and to produce sound the amps, volts, and ohms and such need to be at a certain level or you couldnt hear the music or your ears would explode
so in a way the capacitor is also used as a resistor of sorts.
hopefully that helped you
p.s. you could always ask google
AndyGadget6 years ago
HERE is a very, very, very simple synth.  The capacitor here sets the range for the output frequency.  A higher value capacitor takes longer to charge and discharge through the resistor so the tone is lower than for a lower value.

The feature of capacitors is that they store a small charge and this allows them to be used for smoothing signals or letting higher frequency signals through in preference to lower frequency signals. 
It depends entirely where it is in the circuit.

It's probably part of either a frequency filter, or a resonant circuit to generate an output. If you have a circuit diagram, or a photo of the PCB, someone may be able to tell you its exact function.