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Another use for LM393/LM339 #863
Replies: 3 comments
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Posted at 2016-05-07 by @allObjects ...or are there Hall effect transistors involved? Depending on the type of Hall sensor, no op amp is needed. Check 'old' computer fans for it... |
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Posted at 2016-05-09 by DrAzzy Cute, any parameters on the parts that you could share as an example? Those comparators are spectacularly useful parts. |
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Posted at 2016-05-09 by ClearMemory041063 The anemometers use regular magnets and a coil about the diameter of a nickel wound with #30 wire. Output about 1 Volt p-p max. I've used the LM339 inputs connected to a transformer to get 60 Hz square waves. Just keep the peak Voltage within the LM339 specs. Hall Effect switches are nice too, but the anemometer has a coil. |
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Posted at 2016-05-07 by ClearMemory041063
http://www.espruino.com/LM393
There are some anemometers that use a rotating magnet to induce a low-level AC current in a coil. The output of the coil can be applied to the + and - terminals of one of the LM339 comparators. The open collector output then produces square waves suitable for counting.
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