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Old May 7th 05, 03:55 PM
RST Engineering
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If you take a look at the current pulse during the solenoid pop, you will
find that it is just a little bit over 250 mA (0.25 amp) during the tug, but
the current only flows for a quarter of a second or so.

I recommend a "slow-blow" type fuse for the application where the current
has to exceed the rated current for some period of time before it blows.
The amount of time is dicatated by the amount of current. A short circuit
of ten amps or so will pop it in a few milliseconds, yet it will hold half
an amp for a couple of minutes.

The slow-blow gives you the best of all possible worlds with pulsed current
like this.

See also the Kitplanes article on making your own LCD clock with a Rat Shack
module. Current draw is something on the order of half a milliampere.

Jim



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