how to reduce speed/ amplitude of electronic pendulum??

What you say makes sense -- but the drive circuit will always compensate for losses, regardless of design philosophy.

Therefore, it makes sense to have the pendulum swing a tiny bit slow, and have the drive circuit force it to the correct frequency. This would also make trimming the frequency a simple matter.

To me the way that makes the most sense is to completely uncouple the two functions. The accuracy of the cheapest quartz movement is far better than you can get with the most precise pendulum. The most efficient pendulum is one that oscillates at it's native frequency. Googeling electronic pendulum drive circuit yields a great deal of information, including some designs that simply provide a boost to a pendulum at it's native frequency. Most of the designs did nothing to optimize drive current.

PlainBill

for

Perhaps you could gate the output drive by a divide by 10 counter on the clock ouput and only power kick every tenth swing of the pendulum. Would conserve battery and perhaps less amplitude of swing

ALL pendulums oscillate at their native frequency. They can't help but.

You're missing the point. The pendulum presumably drives the clock gears. If all you care about is "efficiency", switch to an all-electronic clock with an LCD.

If you're going to power the pendulum electronically, it makes sense to have a system that keeps the pendulum running at the "right" frequency. The system I described allows the pendulum frequency to be tweaked without mechanical adjustments.

One trick I have seen used, is to use a magnetic pendulum, and place a drive-and-sense coil immediately beneath the center of its swing. The drive circuit senses the beginning of the inductive pulse generated in the coil as the pendulum swings down towards it, and then sends a drive-current pulse through the coil to magnetize it and attract the pendulum magnet just before it "reaches bottom" in its swing.

There are all sorts of tricks you can play with this approach. You can use a Hall-effect sensor in addition to the coil (separating the sense and drive functions). If you use a coil, you can detect the height of the pulse during the pendulum swing in one direction, and use this as a way of estimating the pendulum's speed... if it's high enough, you don't need to "kick" the pendulum as hard during the next swing (don't drive it at all, or reduce the strength or duration of the drive pulse).

I've seen little "desktop toy" pendulum systems, or "rotating wheel" toys, which use this approach. They can be rather mysterious, if the drive/sense electronics are concealed in the base... the pendulum just keeps swinging, or the wheel keeps rotating, with no visible drive force and no tick-tock sound.

I believe that the Klockit pendulum system being described here, does not use the pendulum to drive the gears. It's described on their web site as a "pendulum case assembly", into which you insert your (separate) quartz clock movement. It has a separate battery.

If this is what the OP was using (as I recall), then the pendulum system is a purely cosmetic add-on to the clock. It plays no part in the drive, or time regulation of the clock itself... those are entirely the role of the quartz movement assembly.

Only true if you add the qualifier 'if there are no additional forces'. A great deal of effort is required to ensure this is true. Did you ever wonder why the best Grandfather clocks use weights to provide power?

In a happier time my wife decided we needed a real pendulum clock on the mantle of our new (to us) home. She picked up one (made in Korea) that required monthly winding. With a little care I could adjust it so it was correct at the begining of the month and again at the end of the month. The force provided by the spring changed depending on how tight it was, this changed the force on the escapement, which changed to force applied to the pendulum. The clock would gain time at the beginning of the month and lose it toward the end of the month.

Look attractive? Yes. Sound good? Definitely. Keep good time - no way.

PlainBill

compensate

would

No, I never wondered, because I knew why. And it's energy, not power, by the way.

compensate

would

If

with

have

Thats why fusees were invented, but could only compensate to a certain extent

is.

Dimensional analysis?

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--------------------------------------+------------------------------------ Mike Brown: mjb[-at-]signal11.org.uk |

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what it is.

That's it! Thank you.

Efter mange tanker skrev N_Cook:

Not all people "run slow". Some "run fast". These are the people with the nasty habit of waking up at 5AM pestering the other half until the early birds go to sleep when the late risers want to have fun.

If you are locked in the office/shop/factory all the hours with daylight, and never seeing the light of day during the winter, you can get depressed; this can be reduced by, in the morning, looking into a strong "wake-up-lamp" designed to have the spectrum of sunlight.