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Project Notes

#234 CMOSInverterOscillator

Use a CD4096 to generate an oscillating waveform and plot the results



I found this oscillator circuit as part of the LEAP#182 PowerSupply317Kit.

It is another variation of the basic Schmitt Inverter Waveform Generator pattern, which I tested in LEAP#022 SchmittOscillator.


… is quite terrible actually. Oscillation is only sustained for a small sweep of the 100kΩ pot. The waveform is also heavily asymmetric - with a duty cycle at most 25%.

Setting C1 R1 (pin 2-3) Frequency
max sustained oscillation 10µF 2.5kΩ 27Hz
min sustained oscillation 10µF 40kΩ 0.4Hz
max sustained oscillation 1µF 2.15kΩ 165Hz
min sustained oscillation 1µF 40kΩ 4Hz

Scope trace for C1=1µF, R1(2-3)=2.15kΩ:


Scope trace for C1=1µF, R1(2-3)=40kΩ:




The Schematic


Credits and References

About LEAP#234 CMOSOscillators
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LEAP is just my personal collection of projects, usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting (IMHO!).

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