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Lots of Makers are sending in great projects for Halloween that use the 555 timer chip, so here's another resource to get started for all your LED blinky needs - "Timer circuit has been used in many projects and there are basically 2 types that are used these days. One of them is the use of analog RC circuit where charging of the capacitor circuit determined the T(time) of the circuitry. This type of circuitry has larger tolerance and is used in applications where the T is not so critical as the T is affected by the tolerance of the RC components used.
The other is the use of crystal or ceramic resonators together with microprocessor, microcontroller or application specific integrated circuit that need higher precision T in the tolerance of up to 5 ppm (parts per million). " - Link.
Related:
I don't know if Radio Shack still sells them, but the "engineer's mini-notebook" on the 555 by the venerable Forrest Mims is a great reference on all kinds of things to do with the 555.
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The radio shacks around here insist that they don't produce books any more. So hold on to your old copies, they're hard to replace.
Unless someone has a secret PDF stash? Anyone?
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Ahhhh, the 555 timer. Hard to beat that chip.
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They don't produce the books anymore.
I have the original from when it was 1 large book. Later they divided the circuits into about 5 books each for the price of the original 1. Now they don't make them at all.
It's sad, Radio Shack used to be a great place for makers, now it's just a place to get overpriced cell phones and satellite dishes if you're too stupid to find a better store.
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I use a 555 for my fog machine. It drives a relay coil that switches the machine on for 15 seconds, off for 1 minute on or something like that. Gotta do it to match the duty cycle of the machine.
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They do still make them, you just have to go right to the source.
http://www.forrestmims.com/engineers_mini_notebook.html
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Question:
Wikipedia's entry about 555 timers has the 7 and 8 ports reversed!
It says 6 is Threshold and 7 is Discharge.
http://en.wikipedia.org/wiki/555_timer_IC
Is that their mistake?
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