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Schmitt Trigger

fx_7

Jan 13, 2016
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Jan 13, 2016
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Hi all
I have a flowmeter sensor which supposed to give square wave but output is a bit different therefore i decided to use a schmitt trigger to convert this signal to square wave.What do I need for this?What are the criterias that i need to consider?I searched on net and realized that i could do this circuit with 2 resistors and 1 omp-amp?

Thank you
 

Alec_t

Jul 7, 2015
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Welcome to EP!
What is the flowmeter output spec? Volts? Open-collector? .....?
 

fx_7

Jan 13, 2016
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Jan 13, 2016
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flowmeter has a digital output let me put the manual ftb 1302 is mine
 

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BobK

Jan 5, 2010
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You could probably use a Schmitt trigger CMOS gate. What voltage are you using for supply?

Bob
 

AnalogKid

Jun 10, 2015
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There are lotsa ways to do this. What parts do you have or have access too. Also, do you prefer to go with analog or digital parts?

1. A CMOS 4093 or 40106 has some hysteresis built into the inputs, and pretty-fast square wave edges at outputs intended to drive other logic circuits.
2. With an opamp (totem pole output) or comparator (open collector output), you have adjustable hysteresis you can tailor for greater noise immunity, but the outputs have slower rise and fall times.
3. You can add resistors around regular or hysteresis logic gates to increase the hysteresis window similar to the opamp/comparator circuit while still having the faster output edges.

ak
 

fx_7

Jan 13, 2016
4
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Jan 13, 2016
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from your replies CMOS 4093 or 40106 seems easy, i can get that parts.Do you need this information but i am using NI 6229 bnc daq.Sensor has digital(counter) output so i have to go with digital parts
 
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