 OT: 555 timer... need a hand with Astable settings :), been a long time... |
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| Mueller |
 Oct 2 2006, 04:05 PM
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914 Freak!  Group: Members Posts: 17,155 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None 
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okay, so I have a device I want to turn on for 10 to 20 seconds via the output going to a relay, off to be a few seconds.
I just downloaded pspice student version to see if I can mimic the circuit which I am not sure if the student version can do so..... using a kit from Ramsey http://www.ramseyelectronics.com/downloads/manuals/UT5.pdf other res. I have on hand are 1M (variable), a couple of 100K and a bunch of 1K....for extra caps, 100uF is the max |
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| Tom |
Oct 2 2006, 04:24 PM
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Advanced Member Group: Members Posts: 2,139 Joined: 21-August 05 From: Port Orchard, WA 98367 Member No.: 4,626 Region Association: None |
Mueller,
If I remember right you find time in seconds by multiplying capacitance X resistance. Using mico farads and meg ohms the numbers work easy. 100 micofarads X 1 meg.the micro farads and megs numbers cancel out ( .000001 X 1000000) =1. So with a 100 micro F capacitor and 1 Meg resistor you would get 100 sec. If you want 10 sec use the 100K res. Ie one 10 the resistance of the 1 meg. Hope this helps. I experminted with a 555 and 556 to get a simple alarm circuit to work and as long as the out put was way very low in current , I had success. As soon as I attempted to have the output set or unset a relay , the circuit would fail. Tom |
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Posts in this topic
Mueller OT: 555 timer... need a hand with Astable settings :) Oct 2 2006, 04:05 PM
bd1308 thats why it may have helped to put the output int... Oct 2 2006, 04:47 PM
jkeyzer Hey Mike,
The 555 datasheet has a reference circu... Oct 2 2006, 04:58 PM jsteele22 Hey Mike,
Here's a datasheet for the LM... Oct 2 2006, 05:04 PM Mueller google and ye shall find :)
555 timer calculator.... Oct 2 2006, 05:26 PM davep Some of the datasheets are flakey also. I forget w... Oct 2 2006, 06:46 PM |
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