Schmitt trigger oscillator using the CD4093

A very simple and reliable oscillator can be made using the CD4093 CMOS Schmitt trigger. It will oscillate easily and can reach very low ( mHz or lower) frequencies. Higher frequencies are somewhat limited owing to the limitations of the CD4000 series logic. Nonetheless, this oscillator is truly a very useful circuit to know and can be put together very quickly. Supply voltages of 5.0V to 18V can be used. Signal Processing Group Inc.has recently released a simple EXCEL spreadsheet that can be used to calculate the frequency of this oscillator given the resistance, capacitance and the Schmitt thresholds. Interested readers can access this spreadsheet from the “Free items…” part of the SPG website

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