A 7400 frequency counter, on perfboard


jaeblog published a new build:

I like perfboard, especially the ones with plated trough holes. But I also like SMD components, and more and more fun IC’s are not available in DIP. So a while ago I designed some perfboard with 1.27mm pitch, making some SMD parts like SOIC stuff easy to prototype on it, and also mix THT and SMD stuff.
Looking for a nice little project to build on it, I came across a frequency counter made with 7400 logic, perhaps not the most efficient approach, but a fun one at that. I made a few changed to the design, partly because of some components I already had like the 74HC160 and 4543 (yes, not 7400 but still logic :P) and partly to improve on the design, for example by adding a 10Mhz oscillator instead of a NE555 as the clock source. The current end result looks like this, a case is ordered and a follow up post will be made when the project is nicely tucked away in a case.

More details on Just another electronics blog.

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  1. A refreshingly ‘oldskool’ take, although probably using rather more chips than required and face-palming at length is hard to avoid at the author’s failure to grasp that those counters are supposed to be cascaded by clocking them in parallel, using the rollover to _enable_ the next stage instead of daisy-chaining rollovers to the next clock through extra inverters. I swear, kids these days…

  2. Reminds me of the Radio Shack frequency counter “kit” back in the 70’s. I built it as a kid buying a few chips at a time.

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