On 06/16/16 15:50, Lennart Sorensen via talk wrote:
On Thu, Jun 16, 2016 at 11:55:12AM -0400, Scott Allen wrote:
My first computer, a Poly-88 8080 based system, did (I still have it). <http://www.polymorphic-computers.com/poly88.html>
OK, certainly a long time ago.
The transformer used for the linear power supply was tapped, rectified and clamped to feed to an interrupt pin. The interrupt routine would increment a counter in RAM which was accessible for real time calculations.
That's neat.
You know of course that the grid frequency is only approximately 60.00 hz. For example, it was 59.97 hz on Friday at around 5 PM. I have heard rumors that the generators spin the grid up to above 60 hz in the early morning hours to compensate for the drift, but I don't know if thats a fact. I often see the grid at 60.01 hz, in the middle of the day though. -- Michael Galea