This is calibration frequency standards for digital clock circuit.
When you have finished building your digital clock circuit kits, with any ICs number. But how to
which normally we will be get the standard frequency signal of AC power line 60Hz (North America the power line frequency is 60 cycles per second or 60 Hertz) that is a sine wave and then is converted with the Pulse Generator circuit become to square wave form of 60 Hz .
But when we need to use it in the car or others DC power supply. How to it still work well?
We so built the circuit of the pulse generator of 60Hz, to replace the old ways. You may also be adapted to backup set , when the power goes out. We do not have to waste time re-scheduling.[...]
Read more source: http://www.eleccircuit.com/60hz-clock-pulse-generator/