Questions tagged [schmitt-trigger]
Anything related to Schmitt trigger circuits. Schmitt triggers are positive feedback comparator circuits exhibiting hysteresis.
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Using CMOS Schmitt trigger inverters in quartz crystal oscillator circuit
In all sources I've seen about quartz crystal oscillators using CMOS inverters there's a note like this:
But why Schmitt inverter is needed? Won't classic 74HC04 work?
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tunable Wave form generator design with op-amps Multisim
I need to simulate a waveform generator using Multisim. I used the design in this Link. the frequency is 1KHz.
It works fine but I need some modifications:
1. I need the peak to peak voltage(Vpp) to ...
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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 ...
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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 ...
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Pull-up resistor causing unintentional voltage divider?
I'm trying to use the output of a comparator as the input of a schmitt trigger built with positive feedback on another comparator. Both have open collector outputs. When the two are not connected, ...
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How can I transform this circuit so that the output voltage not depending on the supply voltage of the amplifier(V2 and V1)?
I have to modify this circuit so that the amplitude of the output signal be the same,everytime I change the value of V2 and V1...How can I do that?
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Using a Schmitt-Trigger to transform sine to square wave
I have a myRIO from NI. I use the FPGA to generate a sine and a cosine digitally for signal processing of a photo acoustical signal. The sine and cosine have the same frequency. I now want to output ...
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Disadvantages of Schmitt Trigger Inputs
I'm familiar with the utilization of Schmitt Triggers when interfacing with low slew rate signals / sinusoidal waveforms. In a recent design, I've been scrubbing our FPGA I/O configurations and ...
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How can I implement a schmitt trigger into a differentiating op-amp in order to reduce the signal noise of the output? [closed]
The circuit is driven by an LDR, but the output signal is too noisy. Is there a way hysteresis can clean up the noise in such circuit?
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How to implement programmable Schmitt trigger?
I am trying to build a Schmitt trigger that would allow adjusting High and Low threshold values with a microcontroller.
simulate this circuit – Schematic created using CircuitLab
I could ...
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Help in finding capacitor and resistor value for discharging circuit
I'm newish to electronics and I am trying to make a circuit that charges a capacitor, then discharges it when a switch is closed. The signal then goes into a schmitt trigger to be cleaned up. The ...
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What could cause a sawtooth waveform to have these gaps in between?
I'm having problems with these gaps in between the sawtooth waveforms produced by a free-running bootstrap ramp generator triggered by a schmitt trigger. Why are they occurring and how could I fix ...
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Trying to calculate UTP and LTP of opamp circuit
I'm doing a practise test and one of the questions is asking me to find the upper trip point (UTP) and lower trip point (LTP) of the following circuit:
I'm not sure how to do it with a circuit of ...
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Two-tone alarm issues
I'm working on an inclass project, for a two-tone alarm circuit. The 3V source represents two AA batteries. We've implemented this successfully on a breadboard. The IC used for the Inverted Schmitt ...
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Versatile input termination / translation for reference clock?
I've got a microcontroller I want to clock from an external 10 MHz reference. I'd like the reference input to be as versatile as possible. At the moment, my reference is an LVCMOS square wave, but ...
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Understanding Schmitt Trigger from datasheet
I've asked this question before, but I don't think I worded it correctly, as I got answers to a question I didn't intend to ask... So I'm giving it another shot:
I am having some difficultly ...
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Schmitt trigger design to control lead acid battery charger
I've found a very good explanation on schmitt trigger circuit design here -What is a Schmitt Trigger and its application exactly?
But the design is done considering same reference voltage and the ...
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Solving Schmitt trigger circuit using the superposition theorem
In order to solve a Schmitt trigger circuit implemented with an op-amp (or a comparator) connected in positive feedback, this wikipedia page uses the superposition theorem.
My question is : why can ...
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Do Schmitt-trigger specs give requirements to avoid metastability?
Although Schmitt triggers are not usually regarded as latches with setup/hold constraints, a Schmitt trigger is functionally a sort of latch which is forced one way when the input is above a certain ...
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In a 74HC14 Schmitt trigger IC, unused inputs/outpus
I have a 74HC14 Schmitt trigger IC. I only use one of its I/O pairs, and everything else is not used.
I understand that in TTL logic the unused inputs should be set to either high or low to prevent ...
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Discrete Schmitt Trigger: make output logic level at 0V, not 3V
I designed a Schmitt Trigger with discrete components (using an emitter-coupled pair) that operates with a Low Disable Trigger of around 3.5V and a High Enable Trigger of around 4V on circuit ...
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Questions on this high frequency sawtooth generator
So I found this very basic sawtooth generator:
http://www.radiolocman.com/shem/schematics.html?di=143990
I have a few questions about it:
I understand that when the capacitor C_T charges fully to a ...
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Schmitt Trigger Functionality Not Working, Questions
I'm trying to build a Schmitt trigger like the one described here: http://pcbheaven.com/drcalculus/index.php?calc=st_nonsym_sp
However, it isn't working as expected, and I'm thinking it may be due to ...
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What is the current source for in the Schmitt trigger?
What is the current source for in the schmitt trigger? I can't understand this. Can't see any resistor either.
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Schmitt Trigger Oscillator - How does it work?
I have seen countless times the following diagram for a Schmitt trigger oscillator.
As shown in the picture, the slow-rise wave-form generated by the charging and discharging capacitor is translated ...
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How to understanding min/max input values of Schmitt Trigger from datasheet
I am having some difficultly understanding the values described in this product sheet for the SN74AHCT14 Schmitt Trigger Inverter:
http://www.ti.com/lit/ds/symlink/sn74ahct14.pdf
Given a Vcc of 4.5V,...
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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 ...
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Schmitt trigger
Why does feedback on the inverting pin and input on the non-inverting pin result in an amplifier (non-inverting amplifier) while feedback on the non-inverting pin and input on the inverting pin result ...
user70513
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variable inverting op-amp Schmidt trigger
I need to have variable high and low thresholds. Where do I put a variable resistor to get better results?(R1,R2 or R3)
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How to derive the node voltage for this comparator with hysteresis?
I have the following circuit. U26 is a simple unity buffer and U15 is just a dual comparator.
I want the top comparator to compare the battery voltage (VBAT/2) on the inverting input with 2.0V ...
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Why does a Schmitt trigger work in saturation region?
Given this circuit
simulate this circuit – Schematic created using CircuitLab
I am trying to prove that the opamp works in saturation region as instructed in the first answer to this question :...
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Pull up resistor on Schmitt trigger IC input?
I have two different circuits on two different boards. The output of board A, let's say, is optocoupler based and hence, it has a pull up on it. This signal is connected to board B through an ...
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All sorts of fail converting Schematic to Bread Board
Schematic:
Fritzing BB View:
Total n00b: I am trying to layout my breadboard based this schematic, but I'm not sure if I've even come close. The LM34 in the graphic is actually a SS494B hall effect ...
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Schmitt Trigger Inverter
I have this project where I'm meant to design a changing frequency circuit using schmitt triggers. It cycles between 2 frequencies. In the below circuit, pretending the not gates are schmitt inverters ...
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Switched-mode constant current supply with Schmitt Trigger
I'm planning on building a small constant current power supply for charging lithium-ion batteries on the go. While they normally use constant current AND constant voltage, I've elected not to include ...
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74HCT14 schmitt trigger doesn't improve rise/fall times
I have a square wave signal whose rise and fall times are too big to feed into another 74xx-series logic chip, such as the 74HC175 flip-flop, which requires rise and fall times in the nanosecond range....
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What is a Schmitt Trigger and its application exactly?
i would like to ask about what is a Schmitt Trigger and about its application.
I searched a lot but still didn't understand it. Please explain step by step and hope you help me in its applications ...
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Schmitt-Trigger with Simulink
I have a problem with simulating a Schmitt-Trigger and analyze it with MATLAB. I can do this with MultiSim or Proteus but for more advanced analysis I need to do this in Simulink.
In Library Browser ...
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74HC86 XOR datasheet say Schmitt trigger "action" - is there anything special about it?
I current have a Schmitt trigger chip to clean up an output from one of my optical encoders and I am thinking about using an XOR gate to feed in both encoder outputs to double my encoder output ...
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Working of Hex Schmitt−Trigger Inverter as a Sawtooth and Square Wave Producer
Can someone explain how a Schmitt Inverter can behave as a Sawtooth (on pin 1) and a Square wave (on pin 2) as produced in a circuit where we have a Capacitor between pin 1 and GND, and a resistor ...
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Should I worry about an initial negative voltage?
I'm building a circuit that I found online for measuring spark-plug pulses and it seems to give a clean enough slope for my micro-controller interrupt, but it has an initial negative voltage.
Is this ...
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Difference between TTL I/O type vs Schmitt trigger I/O type
While reading microcontroller data sheet i came across i/o types like
i) TTL
ii) schmitt trigger.
I came to know that TTL i/o logic means 0v-0.8v -logic state 0, 2-Vcc means logic state 1 (as ...
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threshold problem on a Schmitt trigger op amp
I have the Schmitt trigger op amp on the below diagram. (channel A & B refers the oscilloscope probes on the following figures).
The resistor values are selected to set the trigger threshold as ~...
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555 Schmitt Trigger works well with CMOS LMC but not NE555?
I have an NE555 (the non-CMOS version) running in astable mode at 118Khz. I have the output pin3 connected to input for a second 555 running as a Schmitt Trigger to invert the signal. What I found is ...
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increasing output voltage of a schmitt trigger op amp
I have the Schmitt trigger circuit below that I read the output as 1.6V for the logic High. I wonder how can I increase the output voltage of the comparator below without changing the threshold of the ...
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non-inverting schmitt trigger op amp - replacing a zener diode on the input
I wonder if it is possible to replace the second figure below with the first one? Would both Vo output be the same on the figures below? If they are different, ...
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How can I test a hex Schmitt trigger?
Yay, me...I just got done soldering my first surface mount IC. Because I know how volatile heat can be, and with how close the tip of my iron was to the IC (especially without a socket!), I'd like to ...
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How do I make an opamp comparator work in schmitt-trigger mode?
I want to control a small 12V case fan. I will set values of R1, R2 and R3 so that the fan will work above temperatures 40oC.
I understand that in these kind of systems, there will be an indecisive ...
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Comparator with hysteresis equations
I'm trying to be sure I'm computing the values for this circuit right. Here's an example of the circuit I'm trying to build (it's going in a 12 V DC system, so I filled that in already).
I have ...
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