DIY VCO Part 4: Shaping Sawtooth to Square

Support the channel: Buy as a DIY kit: Ebers-Moll-Model: #Ebers–Moll_model René Schmitz’ Page: In this series, I’m taking a detailed look at how to build an analog VCO from scratch, using just a handful of cheap components. It’s the basis for any synthesizer. To keep it as beginner-friendly as possible, I’m explaining what all the components do in detail. In this fourth episode, we’re adding a variable pulse width output to our oscillator. Other new features include added stability through thermistors, a fine tuning knob and modular-conform volume levels (10V peak-to-peak). If you want to follow along, here’s a bill of materials: 2x 100k Linear Mono Potentiometer 1x 1 uF Foil Capacitor 1x 1N4148 Diode 1x 1M Resistor 1x 200k Resistor 3x 100k Resistor 1x 33k Resistor (sorry, I misspoke – it’s not 32k) 1x 20k Resistor 3x 10k Thermistor NTC Chapters: 00:00 Intro 00:38 Temperature Trouble 01:48 Thermistors Basics/Taming Transistors 02:43 Temperature Dependent Voltage Divider 04:37 Thermistor Setup 05:13 Fine Tuning Intro 06:53 Weighted Voltage Divider Inputs 08:01 Fine Tuning Setup 08:34 Waveshaping Intro 09:11 40106 Sawtooth-to-Pulse 10:56 Op-Amp Basics 11:56 Op-Amp Maths 13:08 Op-Amp Negative Feedback 15:13 Non-Inverting Amplifier 16:45 Amplifier Setup 17:25 Amplifier Function Test 18:01 40106 Sawtooth-to-Pulse II 20:16 Sawtooth-to-Pulse Setup & Test 21:04 Amplifier Range Fix 21:31 Amplifier Range Fix Setup & Test 22:15 Offset Voltage Removal 22:40 Volume: 10V Peak-to-Peak 24:15 10V Peak-to-Peak Setup 25:02 Sound Demo 26:05 Outro