This is an old revision of the document!

Table of Contents

Voltage Controlled Oscillator

This is a small Voltage-Controlled Oscillator - the heart of every analog synthesizer. It provides a square and a triangle wave, and it could be hard synced, too.


The OpAmp is a rail to rail MCP6002 from Microchip.

It is designed to use for experimts and development together with a breadboard.

Schematic


Paper PCB


vc_oscillator_12.zip

Parts

  • Resistors:
  • 1x 1 kOhm
  • 2x 10 kOhm
  • 1x 12 kOhm
  • 6x 47 kOhm
  • 1x 100 kOhm
  • Capacitors:
  • 1x 3.3 nF (foil)
  • Electrolytic Capacitors:
  • 2x 10 µF
  • Semiconductors:
  • 1x LED
  • 1x OpAmp MCP6002
  • 1x BC547 transistor
  • Mechanical:
  • 1x IC socket, 8 pin
  • 2x pin strip 3 pin
  • Potentiometers:
  • 1x 100 kOhm

Voltage In

Any voltage between 0-5V at the VIN pin can control the frequency. Without input resistor the potentiometer wont have any effect on the frequency. But depending on the value of the input resistor the potentiometer will change the frequency, too. 

 Voltage Source-------10 kOhm-------- Voltage In

Sync

For the Sync input one can use any 0-5V source a diode is needed. An additional resistor will decrease the syncing effect.

 Sync Source -----/\/\/----->|-----Sync Input

Output

If one wants to use it as a sound source one needs to attach a resistor and a 47µF capacitor to the output:

                          +  47µF
 square out----470 Ohm-----||-------Line Out
                        |
                      120 Ohm
                        |
                       GND


                            +  47µF
 triangle out----470 Ohm-----||-------Line Out
                         |
                       150 Ohm
                         |
                        GND

License

The Voltage Controlled Oscillator was designed by Wolfgang Spahn 2020.
It is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

Creative Commons License