HOW TO – Crystal controlled 1 pulse per second clock

Fig 3 Project 10202006
The latest Citizen Science has a how-to on making a pulse circuit from a clock, the completed circuit provides pulses with a duration of about 30 milliseconds… Allan writes – ” This easy to make circuit will provide pulses at a highly accurate rate of one per second (1 Hz). The circuit is based on a common quartz clock movement that seems to be in most of today’s wall clocks. A suitable movement can be salvaged from a clock or purchased new from a hobby shop. “Link.


  • Electronics projects @ MAKE – Link.
  • Society for Amateur Scientists. Citizen Scientist – Link.

4 thoughts on “HOW TO – Crystal controlled 1 pulse per second clock

  1. DonTron says:

    This is a clever circuit! Probably could just have used an NPN bipolar transistor, rather than the lm339 comparator, in common collector mode, by feeding both diodes into a base resistor, to acchieve the ‘OR’ functon.

  2. Tobin says:

    I was disappointed to find that this project amounts to “build a clock… using a clock!” I would be much more interested in an article explaining the characteristics of the little “tin can” quartz oscillators and how to wire them up.

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