Learn About the Voltage for Homemade Synthesizers

Video Transcript

This is Loren Parker with Expert Village, and I'm talking about how to make your own oscillators for a musical synthesizer. So here is our basic oscillator. We've got one chip, and we have a couple of components surrounding it, very simple components. And this is a battery powered oscillator using two double "A" batteries to provide three volts of power to this. And you can find all of these components at suppliers like All Electronics on the web, or at a local electronics store. Now the batteries are going to provide power, they're going to provide voltage, which is a fundamental part of anything electronic. As soon as I apply that voltage, we get kind of a buzzy, reedy sound out of the oscillator. But controlling the frequency is not the voltage, that's what's providing the fat power, what I have controlling the frequency here is this knob, and notice that the sound went away when I turned the knob up. The sound actually didn't go away though, the sound now is so high pitched we can't even hear it. My dog can probably hear it, but human beings can't, so I turn it back down, and now it's in the range of human hearing. So, what's happening is this knob is controlling the timing, it's controlling the timing between where the circuit turns on, goes high, turns off and goes low. It's controlling the wavelength of that oscillator, the pitch, and in this case when we have a lot of resistance from our potentiometer here, we are creating a lower pitch. When we have less resistance, we are creating a higher pitch. And in any electronic oscillator, you need two components. You usually need a resistor, which is this knob right here and you need a capacitor, which is this guy right here, this little disc looking thing, and they look like these guys right here. And what happens is that the capacitor fills up with electricity, and then releases it at intervals. And the relationship between how much resistance and the rate at which this capacitor is filling up and then releasing like a reservoir, determines how fast our oscillations go. The faster they go the higher the pitch, and thus we're able to control the frequency of our oscillator. So voltage from the batteries goes through this circuit, the amplifier is the chip, the feedback goes through the resistor and the capacitor which time it, and that timing determines the frequency. That's how we tune our oscillator, in a nutshell.

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