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How to delay a pulse (1-400Hz @ 12V) from 0.1mS to 1mS?

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rx5

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4538 delay

Hi,

anybody have idea how to delay a pulse (1-400Hz @ 12V) from 0.1mS to 1mS??

thanks!
 

pulse delay circuit

Two monostable multivibrators. The first detects the leading edge on the input pulse and outputs a pulse of the desired delay length (0.1mS - 1.0mS). The trailing edge on the first monostable's output triggers the second monostable, and that outputs a pulse with the same length as your original pulse. This assumes that your input pulse has a fixed width, even though the frequency varies (1Hz-400Hz).

Ken
 

Pulse delay

Ken,

I wonder if it can be done with a two 555's wired as monostable??
 

Re: Pulse delay

What is the input pulse period, and direction...+>->+ or ->+>- ?

Ken
 

Pulse delay

+12V/GND pulses... snappy turn on/off(schmitt like) more of the GND, than positive pulses...


Ralph
 

Re: Pulse delay

Ralph,

Again...is the positive or negative period of the signal a fixed width (for example: 1.0mS positive for a any frequency between 1Hz and 400Hz.)? Or. is it like a square wave where the periods of both the positive and negative portions vary with the frequency. This makes a big difference!

Ken
 

    rx5

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Pulse delay

Ken,

OH I see...sorry... well, its from a signal pulse(from ignition pulser) so width of positive(or negative) varies ... pulse width will be shorter in duration at higher frequency(400Hz) ... its mainly a "positive" pulse...

1_1203864702.jpg



EDIT: I have found such a circuit already (googled) 4538

thanks a lot for the help!! :)

actually, this is just PART of what I want to experiment on... as frequency INCREASES, the pulse delay would INCREASE and vice versa... need a way to inversely affect pulse delay timing resistor....

Ralph
 

Re: Pulse delay

This definately will not work with my approach. :(

How will the 4538's delay time change with the change in input frequency?

But it might ba a job for a microcontroller like a PIC. The signal rate is slow enough that it could even be handled by an interpreted BASIC chip like a PICAXE. Is it possible for the system to delay the output one full pulse cycle before it outputs a delay, so it knows how long the pulse is, and adds a lookup-table defined delay to the beginning and end next pulse and subsequent pulses?

Ken
 

Re: Pulse delay

KMoffett said:
How will the 4538's delay time change with the change in input frequency?

Ken


thats HOW I am going to figure out.. maybe use an LED/LDR.. many ways.... I think its much simpler for a PIC...

Ralph
 

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