build a synthesizer for like a couple bucks
We're building you a synth out of parts that are so cheap, you're only a couple bucks away from your housemate telling you to put on headphones.
Last issue, we built an oscillator out of the control voltage gate and an op amp chip, source, the lower the resistance and the source (output) voltage relative to the drain (input).
This issue, we're going to make it some resistors, and the potentiometer. This issue, we're
What you're going to do first is build another one just like the first one (go on, do it now), and then you'll use one of them to control the other with frequency modulation.
You'll need a new kind of part, and you should get a pile: 4x 2n7000 MOSFETs (get a bunch – it's $1.80 for 10 of them on digikey.com right now) – a Metal Oxide Silicon Field Effect Transistor. It's literally a tiny teleporter. Unfortunately, it only teleports electrons a tiny distance. But it will take you to another planet. Let's hope there are Tamarians there and not Gorn.
Transistors (especially MOSFETs) are like resistors that go from $\Omega$ to $\Omega$ by each other! Once your synth is putting a voltage into a working you're making artistic third pin called a gate. Ducsions. Turn the knobs and see electricity drains into one side what they do. Connect the outputs to of the transistor and you can source headphones or speakers (that's the tip electricity (both voltage, that we use and sleeve connectors of an aux for signal; and current that we use to cable). Connect them to LEDs (and a actually power things like speaker resistor, or they'll blow out!) comes) from the other side. The higher
oscillator 1
(frequency control)
square wave output 1
oscillator 2
triangle wave output 2
Here's what the 2n7000 transistor looks like IRL. Other transistors might have pins in a different order, so you have to make sure by looking up the component's datasheet. I like this particular one because it works well at the voltage ranges we use and doesn't have much of a "dead band" before it starts conducting electricity. If the knob isn't working to change frequencies though, try plugging the power from the batteries into the gate to open it all the way, instead of it being turned up and down by the incoming signal. After all voltage is voltage, whether it's coming through an audio signal or from a battery.
Source / Source Gate / Gate Drain / Drain
tip/left (probably red) ring/right (probably white) sleeve/gnd (probably black or raw metal weave)
sleeve/gnd ring/right tip/left
Man Jumping to Heaven dives to Hell for a little vacation. His haunting compositions are tight, complex, and are as much a product of his autoharp as of his electronics.