For a small project, I needed a rectangular pulse generator that could generate positive and negative voltage pulses. These positive-negative pulses are measured with an Arduino to check if the load is still open. When the voltage drops to zero (short circuit at the load side) the Arduino notices it and does something. Additionally there should be two parallel circuits, although the main challenge does not change with that.
- Why positive-negative pulses? - It is required by the application. And true negative voltage is needed, virtual ground solution is not sufficient.
- Arduino cannot measure negative voltage!? - True and therefore only positive side of the pulse is measured.
For the rectangular pulses first one needs both positive and negative voltage. That will be the first topic. Thereafter different pulse generator circuits are shown and finally the chosen circuit is shown. Consequently different circuits as schematics and the measured curves are shown.
I have already long time noticed that it is not very convenient here in Instructables to add clearly several figures, thus I wrote the Instructable and attached it as a pdf.
Hopefully this Instructable help somebody who needs a short summary how to generate limited negative voltage and build a rectangular pulse generator.
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