1)With the oscillator we’re studying the comparator outputs a square wave and the integrator outputs a triangle wave
2) With an integrator, if Vin is positive the output voltage ramps down. If Vin is negative the output voltage ramps up.
3) With a comparator, if the op amp’s + input is connected to a greater voltage that that connected to it’s – input, the op amp’s output will be about positive 9v DC. If the op amp’s + input is connected to a lower voltage that that connected to it’s – input, the op amp’s output will be about negative (positive/negative) 9v DC.
4) There’s a formula for how fast the integrator ramps up or down:
change in volts per second at Vout = -Vin / RC
So the bigger the resistance R you use the slower the ramp gets, and the bigger the capacitor gets the slower the ramp gets.
5) The circuit at the end of this video is a monophonic synthesizer – it can only output one tone at a time. What do you think would have to do to make a polyphonic synthesizer that could play 2 notes at the same time? 3 notes? 4 notes? 100 notes?
The reason the synthesizer could only output one note at a time was because the circuit only had one comparator and one integrator. To increase the amount of notes in the synthesizer there would need to be more comparators and integrators.
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