Electrical Engineering Stack Exchange
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Questions tagged [schmitt-trigger]

Anything related to Schmitt trigger circuits. Schmitt triggers are positive feedback comparator circuits exhibiting hysteresis.

Anything related to Schmitt trigger circuits. Schmitt triggers are positive feedback comparator circuits exhibiting hysteresis, i.e. the input threshold for which the comparator output changes state depends on whether the input signal is increasing or decreasing. This mechanism allows for greater noise immunity.

See also Wikipedia on Schmitt triggers.

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Is a Schmitt-trigger output’s rise time affected by input pulse’s rise time?

I know that a Schmitt-trigger makes rising edge of an input pulse sharper. But is the rise time of the output pulse affected by the input’s rise time? How can this be shown by simulation or shown mathematically with an example?
GNZ
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Confused about Schmitt trigger not working

I have a moisture sensor that I want to connect to a Schmitt trigger so when it reaches the upper voltage, the op amp goes high for watering. It shouldn't turn off until it reaches a lower voltage, then not turn back on again until the upper (dry)…
Dale Woods
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Maximal resistance in series with input of 74LS14 Schmitt-Trigger-Inverter

I was experimenting with a 74LS14 Hex-Schmitt-Trigger-Inverter (datasheet). I notice that with the input pins are not connected, the output pins are low. Furthermore when I had a 10k resistor in series with an input, it wouldn't react to any voltage…
flawr
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Determining U_ref on Schmitt Trigger

If I have only starting values a U_high=3V and U_low=2V (pulse signal on V3 on schematics), can I determine a U reference, that's given us on the inverting input of the op. amp.? My calculations were: Uref = (U_high - U_low)/2 = 2.5V. Is that…
E.Wood
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cd40106 Problems

so im trying to make this simple oscillator using ic cd40106 without any succsess. it's the usual astable multivibrator configuration using a 9v pwr supply, 220k resistor and a 2.2uf capacitor, the output goes through a 100ohm resistor to a red LED.…
OiseauxExotiques
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Some questions regarding a schmitt-trigger design

This question is about a circuit I want to use as a schmitt-trigger and is directly related to my previous question. I modified that and changed the output with suggestion of some users. Here is the circuit: (please click to view the image in…
floppy380
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How to determine low and high threshold levels of a Schmitt Trigger for a known input?

Imagine I have a pulse train input which goes into a Schmitt trigger for getting sharpened. Imagine the HIGH of the input pulse train is around 8V and LOW is around zero volt. So what should one select the lower and upper threshold voltages in this…
user16307
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How to explain the advantage of Schmitt trigger over comparator for pulse conditioning?

Above is the unshaped input pulse train. Red line is the set point for the comparator. I see many pulse conditioning and sharpening circuits use Schmitt triggers instead of comparators. Imagine the input pulse train is not sharp enough so we need…
user16307
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Schmitt trigger IC/circuit with thresholds set by voltages

I want to make a Schmitt trigger for a signal, X, who's thresholds are set by two voltages, A and B. I think I'm having a brain fart. I don't think it's possible to do this with just a single comparator and some resistors, but It would be…
Jodes
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How does positive feedback makes Schmitt trigger faster than a comparator?

Besides eliminating noise, one of the advantage of Schmitt trigger is given as speed. And what I saw that the reason of this is the positive feedback used by Schmitt trigger. Does that mean Schmitt trigger responses input faster so it makes the…
ty_1917
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Difference between Schmitt trigger IC and IC with Schmitt trigger inputs

This is the second time I am facing this question. First time I thought the second time will never come. My question is what is the difference with the Schmitt trigger IC (for example 74AHC1G14) and the inverter with Schmitt trigger inputs…
Nexy_sm
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Schmitt trigger input high 3V threshold and input low 0.1V threshhold or other chip?

Are there any chips similar to a Schmitt trigger but with a wider high low input threshold that trigger high with 3-3.3V and low 0.1-0.2V? I need it to alleviate switch bounce. A comment from the Teensy forum: You want to get it below 1.15 to be…
Radu
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Protect circuit Schmitt Trigger

This circuit is a protect circuit, and I search the google it seems like Schmitt Triger circuit,but I don't undertstand why should need the D1, and I don't know what's the function of D1. Can someone help me to undertsantd this circuit. Thanks
Jitter456
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How to get the full range of output voltage (0-5V) from a differential pair circuit as a schmitt trigger?

The circuit works in the hysteresis range of 2.5V - 1.5V. The output voltage does not reach the full range because I have a dc offset of 1.8V. What's the easiest way to get the full output range with this kind of circuit? Adding a capacitor removes…
Jerzy Przezdziecki
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Flyback driver using cd 4093

In this circuit can any one tell me complete working of ic cd 4093. Mean how schmitt triggering occur in this circuit? And how to draw square wave in different steps of gates? What is the purpose of transisters in this circuit?? I will be thank full…
RC Gilani
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