Discussion in "Electronics" started by    ۞ TPS ۞    Jan 3, 2008.
Thu Jan 03 2008, 05:08 AM
#1

This circuit is a missing pulse detector, i.e., it can be used to detect missing pulses in an incoming pulse train. The main component of this circuit is the 555 timer IC. In this circuit, it is configured as a monostable multivibrator, i.e., a circuit which will output a single pulse every time it is 'triggered'.

Every time a pulse arrives at pin 2 of the 555 timer in this circuit, the 555 is triggered to output a single pulse at pin 3. The width of this output pulse is defined by the values of R2 and C1. R2 and C1 must be chosen such that the output pulse width is slightly greater than the time between each incoming pulse. If the arrival of the pulses at pin 2 is continuous, the output will never complete a single pulse. This is because the 555 timer will always be retriggered and C1 will always be discharged through Q1 every time a new input pulse arrives. As such, the output of pin 3 will always be 'high'.

However, a missing pulse will allow pin 3 to output a complete pulse. This means that it will change its state from 'high' to 'low' after the set pulse width has been attained. Thus, a change in state of the output of this circuit signifies that it has detected a missing pulse in the pulse train arriving at the input.
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Tags missing pulse detector555 timer missing pulse detector

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Sun Oct 13 2019, 07:32 AM
Aline Hutchinson
Hey there,
ExperimenterUK
Sun Oct 13 2019, 03:53 AM
Log in.. then post your code in the 8051 forum
Sat Oct 12 2019, 03:48 PM
Bhadra Sajikumar
i am doing a countdown timer with 8051 for my project, unfortunately our professor had to take a leave of absence before he could teach us most of it.. can someone explain the .asm code of it for me?
Mon Sep 23 2019, 01:07 PM
Nathaniel
I am doing a project for my schools wireless security system with cameras,sensors and spot lights using 8051 micro controller, could you help me out with the design and its source code.
Thu Sep 19 2019, 02:18 AM
Caryn Kover
Thank you for your time,
ExperimenterUK
Tue Aug 06 2019, 12:39 AM
@Ismail ..post in forum, give details
Mon Aug 05 2019, 10:03 PM
Ismail balghmi
Hello. Please I won't download
ExperimenterUK
Wed Jul 24 2019, 06:17 AM
@BUSTER123 Please post in the forum
Tue Jul 23 2019, 11:43 PM
BUSTER123
hello! newbie here. i am kind of a guy who hates using ready - made existing libraries, so this helped a lot as i was trying to control and write to a character lcd display. however, i can't figure out how to set the cursor position. for example, i want to set it to the 5th column in the first row, so position 5. so according to the table, i am sending 10000101 on the 8 data lines of the lcd (register select pulled low). the cursor does not move there however. and i cant move the cursor left or right too. is it something wrong that i am doing? thank you.
ExperimenterUK
Fri Jul 12 2019, 01:25 AM
@ramos https://www.theengineeringprojects.com/2017/09/l298-motor-driver-library-proteus.html

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Posted By [email protected]
Thu Oct 17 2019, 09:38 PM
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Posted By ExperimenterUK
Thu Oct 17 2019, 08:35 PM
Do you understand how this code works?If so, addin...
s_dinesh40@yahoo.com Avatar
Posted By [email protected]
Thu Oct 17 2019, 09:30 AM
i want to scroll message more than 2 dot matrix di...
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Posted By ExperimenterUK
Wed Oct 16 2019, 09:58 PM
What do you mean by "message scroll vertically" ?...
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Posted By [email protected]
Wed Oct 16 2019, 07:38 AM
s_dinesh40@yahoo.com Avatar
Posted By [email protected]
Wed Oct 16 2019, 07:13 AM
message scroll vertically, please share code.
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Posted By ExperimenterUK
Wed Oct 16 2019, 01:10 AM
Which camera ?What do you want the micro to do ?
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Posted By ilylily07
Tue Oct 15 2019, 04:43 PM
i need help.i don't know how to do it.is it possib...
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Posted By ExperimenterUK
Sun Oct 13 2019, 06:10 PM
This code does some scrolling.You will need to fin...
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Posted By ExperimenterUK
Sat Oct 12 2019, 10:19 PM
This code does not scroll, that will be complicate...