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Project Notes

#222 StairStepGenerator

Generate a stair-step waveform with analog components.


Once again I’m inspired to go and build a circuit by yet another great tutorial from w2aew.

I won’t try and repeat the circuit description here - see the video and attached notes. Suffice to say, it is quite an ingenious combination of 3 sub-systems:

  • a “high” (265Hz) frequency pulse (555 timer) provides the charge to step-up the output
  • the step pulse feeds an OpAmp pulse integrator/accumulator
  • a low frequency pulse generator (OpAmp oscillator) provides the reset pulse that clears the accumulator and resets the 555

I’m using an LMV324 opamp, which gives decent rail-to-rail performance. It has a maximum supply specification of 6V, hence I’m running the circuit at 5V only.


This is a trace of the circuit on a breadboard (a little noisy). But it works!

In this trace:

  • CH1: 555 timer signal
  • CH2: reset pulse
  • CH3: output




The Schematic

The Build

Credits and References

Project Source on GitHub Project Gallery Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects. Two main themes have emerged in recent years, sometimes combined:

  • electronics - 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
  • scale modelling - I caught the bug after deciding to build a Harrier during covid to demonstrate an electronic jet engine simulation. Let the fun begin..
To be honest, I haven't quite figured out if these two interests belong in the same GitHub repo or not. But for now - they are all here!

Projects are often inspired by things found wild on the net, or ideas from the many great electronics and scale modelling podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.