PB109 VCO II

An other voltage controlled oscillator. It comes with a really beautifull shaped sinewave - stabel and with the same peak to peak over all frequencies. One can switch between square, triangle and sine wave. In the square/triangle mode one can change with a potentiometer from triangle to saw or the duty cycle of the square wave. In sine wave mode one can shape the sine wave to an interesting “sea saw” wave.
All OpAmps are the rail to rail MCP6002 ICs. For a perfect sine wave one should trim the 500R trim potentimeter to a symetrically wave.


The oscillation circuit is the same like the PB101 Sync VCO.
The shaping from a triangle wave to a sine wave is made with a similar circuit like it's described in: Lab Activity: Generating sine waves from triangle waves by Analog Devices.


Schematic



Paper PCB

Parts

  • Resistors:
  • 1x 15 Ohm
  • 2x 220 Ohm
  • 2x 470 Ohm
  • 2x 910 Ohm
  • 1x 1 kOhm
  • 1x 3.9 kOhm
  • 4x 4.7 kOhm
  • 1x 8.2 kOhm
  • 3x 10 kOhm
  • 3x 51 kOhm
  • 2x 100 kOhm
  • Capacitors:
  • 1x 3.3 nF
  • 1x 100 pF
  • 2x 100 µF
  • Diodes:
  • 1x 1N4148
  • Semiconductors
  • 3x BC547 transistor
  • 2x MCP6002 OpAmp
  • Mechanical:
  • 2x IC socket, 8pins
  • 1x pin strip 1×14
  • 2x pin header, female 90° 1×3, 1×2
  • 2x pin header, male 90° 1×3, 1×2
  • 4x jumpers
  • 2x mini switch
  • Potentiometers:
  • 1x 500 Ohm Trimmer
  • 1x 10 kOhm
  • 1x 50 kOhm