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xambo
Joined: 09 Mar 2009
Posts: 6
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 24 Jun 2009 10:38 false trigger 555 timer |
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What is the minimum pulse width one can generate using a LM555 timer? I could easily get down to 10 microsec but I want it to have 1microsecond. However, this doesn't seem to work by having a resistor reduced by a factor of 10. THe pulses start to have intermediate transistions and distorted. Please help ASAP. Thanks.  -)
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FvM
Joined: 22 Jan 2008
Posts: 5160
Helped: 767
Location: Bochum, Germany
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24 Jun 2009 10:46 max speed of 555 timers |
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| I could easily get down to 10 microsec. |
Easy or not, that's also the minimum pulsewidth mentioned in the datasheet. (You may want to read it).
So you should go for a different monostable IC, e.g. from CD4000 or 74HC family.
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user1111
Joined: 24 Mar 2007
Posts: 56
Helped: 4
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24 Jun 2009 13:32 site:www.edaboard.com timer |
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| first of all go through the datasheet of 555 .
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mfarooq1
Joined: 09 Jan 2009
Posts: 87
Helped: 4
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24 Jun 2009 14:33 74hc 555 timer |
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use 74122, 74123
find it in 74HC series
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baysidebecca
Joined: 27 Jun 2009
Posts: 16
Helped: 2
Location: No. California
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27 Jun 2009 20:25 sharp pulses using 555 timer |
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National Semiconductor makes a fast, low power CMOS version of the 555, the LMC555, which has an (advertised) top speed of 3MHz in astable mode:
http://www.national.com/mpf/LM/LMC555.html
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Google
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27 Jun 2009 20:25 Ads |
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xambo
Joined: 09 Mar 2009
Posts: 6
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30 Jun 2009 19:16 false triggering of 555timer |
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Thanks guys! Can anyone tell me why does a monostable have a false triggering while reducing the time constant? I am having a family of timers.An astable that triggers a monostable which triggers 2 more monostable timers, one of which is there to introduce a delay and then triggering another monostable so that I can get two sharp pulses of variable widths and variable separation. The delayed pulsewidth starts to have an intermediate transition which stops it going below a certain pulsewidth by means of adjustable resistor.
Please don't suggest other means to do the same thing as its too late to make any major change.
Regards to all.
Added after 4 seconds:
Thanks guys! Can anyone tell me why does a monostable have a false triggering while reducing the time constant? I am having a family of timers.An astable that triggers a monostable which triggers 2 more monostable timers, one of which is there to introduce a delay and then triggering another monostable so that I can get two sharp pulses of variable widths and variable separation. The delayed pulsewidth starts to have an intermediate transition which stops it going below a certain pulsewidth by means of adjustable resistor.
Please don't suggest other means to do the same thing as its too late to make any major change.
Regards to all.
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ark5230
Joined: 29 Jun 2009
Posts: 188
Helped: 15
Location: India
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02 Jul 2009 19:18 555 pulse width |
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May be you are working near the extreme working conditions. Quantitative values may help useful suggestions.
Regards
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