This is the way I've chosen to do it. I take the 60Hz from one side of the 6.3V secondary on the power transformer and convert it to a square wave with a couple of diodes and a Schmitt inverter. Then I simply run it through two decimal counters to divide by 10 and then 6. A jumper on the second counter can be used to choose between 50Hz or 60Hz operation if desired.robert gift wrote:Since you would need power to operate that clock, you can count the 60 Hz AC as a timer. Utility companies keep AC extremely accurate.
I've already tested that part of the circuit and it works very well. I sat there for several minutes with a watch to my ear and my eye on the blinking LED that I used as an indicator.
