Counter Circuits for All-Transistor Digital Clock

Thread Starter


Joined Jun 19, 2012
The first digit board is done!

It's a 10-stage discrete ring counter and diode matrix to drive the MINUTES display.
Students are getting some epic prototyping and soldering experience here with the hybrid SMD and thru-hole parts.


The LED filament segments are going to be mounted in a 3D printed frame, seen in Fusion 360 CAD here.



Joined Jan 23, 2018
I find the success with stair-step dividers very impressive. Those used to develop the timing for TV pictures back in the tube days did not use so many steps. And making one work with 60mV steps is awesome! I am glad that a suggestion worked out so well for the class project. It might be very entertaining to run this circuit on simulator software and watch the stair-steps.

Thanks for the update!