Questions tagged [schmitt-trigger]
Anything related to Schmitt trigger circuits. Schmitt triggers are positive feedback comparator circuits exhibiting hysteresis.
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How does this MOSFET-based Schmitt trigger work?
This circuit is an inverting NMOS Schmitt trigger. I'm having trouble understanding how exactly it achieves hysteresis.
If Q3 is removed, this circuit becomes a NMOS NAND gate with both inputs tied ...
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Calculating capacitor charging and discharge time using LM311 as Schmitt trigger astable multivibrator
I need a little help solving some electronics problem. I need to calculate the charging and discharging time of a capacitor in the following Schmitt trigger astable circuit using LM311 I found. If I ...
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SPI device stops working when integrating Schmitt triggers and ESD diodes
I am integrating a BME680 temperature, pressure and humidity sensor using SPI.
When I only use 33 Ohms series resistors, the system works fine. However, when adding Schmitt triggers (NL27WZ17DFT2G), ...
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Issues with switch debouncing
I am having some issues with debouncing a switch with an RC filter and 74HC14 Schmitt-trigger inverter IC. I am using a standard circuit that is linked in the datasheet. The circuit in question here ...
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What is the appropriate VCC to apply to a Schmitt trigger?
I would like to transport a SPI signal over 1 meter, at a 10 MHz clock rate, with each SPI wire twisted with a ground wire, no differential signal, 33 Ohms terminations, ESD protection with chip ...
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Why is a Schmitt trigger useful for SPI?
I understand Schmitt triggers are a great way to convert a floating or noisy signal to either HIGH or LOW depending on a threshold. It is mentioned in other threads that a Schmitt trigger can help ...
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Adding reference voltage to oscillator
I have designed a very basic Schmitt Trigger LFO. However, the power supply for the op amp has to be 9 and 0 V instead of 9 and -9V. For doing so, i supose that i need to add some voltage reference ...
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In the following circuit, do T1 and T2 conduct or block when the circuit is in the LOW or HIGH state?
This circuit is a Schmitt trigger, and the supply voltage Ucc.
is 15V. I want to calculate whether the transistors T1 and T2 are conducting or not when the state is LOW or HIGH(U(A)). These ...
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Why is this not working as a Schmitt trigger?
I've been trying to implement a Schmitt trigger using comparators in LTspice. Needless to say, even though I can work with opamps and comparators, I'm totally at lost with using them to make Schmitt ...
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Time period of V1 and V2 signal the integrator and schmitt trigger
Hello I have tried to solve this circuit several times and i cant figure out what i did wrong.
You guys give me some tips.
This is circuit with 2 op amp (2 stages) first one is schmitt trigger and the ...
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Controlling logic gate and dead time for H-bridge MOSFETs
I intend to make an H-bridge driver for a 36v DC motor that can control with 3 MCU pins (Enable, PWM, Direction), Regarding my research, there are three options to drive the H MOSFETs; One using the ...
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Help me make this switching transistor circuit is right
I'd like some insight to make sure my circuit's design is at its best. At the moment the circuit is working, but since this is my first time designing a circuit from scratch with transistors, I ...
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LM318 strange oscillations
I want to make a 100~200 kHz square wave signal. I tried with a Schmitt trigger oscillator . The circuit below worked well with another op amp but the slew rate was too low so a tried with the LM318 ...
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Op-amp with Schottky diode
I'm struggling to understand what the sense is of using the two Schottky diodes in this excerpt of a circuit:
I understand how a Schmitt trigger works. The diodes ensure that the voltage difference ...
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Schmitt trigger using CMOS inverters [duplicate]
How does this circuit exactly work?
Source: Problem 8.14, Introduction To Digital Microelectronic Circuits by K. Gopal Gopalan
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How do I derive the frequency of an LFO circuit?
I'm attempting to solve why the frequency of an LFO, which is a Schmitt Trigger - Integrator LFO, seems to be about 7.13 Hz even when the reverse logarithmic potentiometer is set to its lowest setting....
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How fast can a Schmitt trigger operate? Can I use it for signal conditioning digital serial data?
I would like to know if I could use a Schmitt trigger chip (e.g., 74HCT14, CD40106B and 74AC14) to clean a 12MHz serial digital signal that has gone through a long cable and will pass through multiple ...
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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, ...
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Frequency detector/comparator problem
I have recently learned about schmitt and comparator op amps, and I came up with an idea to build a "frequency comparator" (if it is called like this). The function of this circuit is to ...
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Analog voltage signal threshold to latch output
I am an aerospace engineer by trade, but currently working on a little side project that involves some basic electronics now. So go easy on my ignorance ;)
Here is a description of what I want to ...
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op amp positive feedback Schmitt trigger
I have recently come across the op amp Schmitt trigger presented in 3rd edition art of electronics. I decided to build the circuit myself in circuit lab, and I have some questions regarding its ...
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Design and Construction of a Schmitt trigger by using NPN transistors [closed]
I try do it using mutism but fail...anyone help
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Match function generator output phase to line phase
I am new here so my apologies if I am missing pertinent details. I am trying to cancel a 60Hz EM field by sending a small 60Hz AC current through a loop of wire that I am generating with a function ...
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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 ...
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Schmitt trigger transistor duty cycle
I built this Schmitt trigger using transistors (2N3704).
Input is a square wave coming from an OCXO, 1 MHz, 50% duty cycle.
I obtain a square wave with 70% duty cycle. What can possibly be the cause?
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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 ...
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Comparator with hysteresis equation for Vmax Vmin
In a scientific paper (Design Considerations for Current Transformer
Based Energy Harvesting for Electronics
Attached to Electric Motor J. Ahola et. al.) I came across the comparator circuit with ...
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Improving waveform shape in discrete Pierce oscillator with Schmitt trigger output
I am making a simple clock source using discrete Pierce oscillator with its output attached to high speed Schmitt trigger buffer to get square wave in the final output.
I got the circuit for the ...
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MCP23017 link to an optocoupler Rail input
In my project I have an optocoupler Rail 32 units like the proto below . I want to link it to my MCU with 2 mcp23017 digital Input . Do I need to put a Schmitt Trigger before the mcp23017 to have a ...
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Laser detector circuit with ambient light rejection
I recently asked how to best detect dropped balls via laser detection.
Someone suggested ambient light rejection by modulating the laser and then filtering the photodetector input for that signal.
I ...
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Opamp-based Schmitt trigger [closed]
I have attached two opamp-based implementations of Schmitt trigger. Output of one will be inverted when compared with the output of the other circuit. Clearly, the difference is in which terminal the ...
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Help to understand how work this halogen lamp power supply
I ask for your help for the following:
Understanding how this power supply works (how the 18kHz are generated).
The role of 100Hz.
How thermal and overload protection works.
How those protection are ...
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Free running ramp generator with negative maximum and minimum voltages
I'm currently trying to figure out how to design a free running ramp generator for a project. I'm required to use op amps for both the bootstrap sawtooth generator and the Schmitt trigger, and the ...
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What is the difference between a hex inverting buffer and hex inverting Schmitt trigger?
What is the difference between an hex inverting buffer (e.g. TC74HC4049AP) and hex inverting Schmitt trigger (e.g. 74HCT14N)?
How can hysteresis be added to a CMOS hex inverting buffer to make it act ...
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LTspice simulation of LM311 comparator with hysteresis not behaving as expected
I am trying to simulate the following comparator circuit with LTspice:
The LM311 comparator was intended to be used with hysteresis, same as the circuit shown in this graph (designators are the same):...
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Sharing clock pulse between different devices
I have an application where i want to use the external clock signal (around 1kHz) with my microcontroller. I am interested in positive edge of the clock which will be detected by microcontroller. I ...
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Origin of the signal in an oscillator composed of a Schmitt trigger and an integrator
Following instructions, we built this oscillator as part of our electronics course:
I was surprised at first that we could get those signals without any initial signal connected to the op-amps input. ...
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How to generate a clock signal using an op-amp
I am trying to build a circuit which toggles a lamp on and off. I am using a JK flip-flop for the toggling action.
I want a clock pulse of 1 Hz. I know there are many ways to generate a clock pulse, ...
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How can I boost the output current of this pulse generator (LF353, supplied with ±15 V) to above 25 mA?
I have a pulse generator design. Everything works fine, but it is required that the output current is above 25 mA. (The 9.69 kΩ is just a variable resistance to modify the output frequency.)
...
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Why is my op-amp pulse generator (LF353) delivering way less voltage (±2 V) than the voltage supplies of the amplifier (±15 V)?
I had to design the following circuit as a pulse generator so that if I vary the resistance the frequency will vary as well. It's defined by the frequency expression:
$$f=\frac{1}{2R_4C_1\ln(3)}$$
...
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Using a Schmitt trigger IC vs making one from op-amps or transistors
In a professional setting, what is the benefit of using a Schmitt trigger IC as opposed to making one from op-amps or transistors? In a high volume application, wouldn't an op-amp implementation be ...
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Does the 74LVC1GU04 actually have "Schmitt-trigger action" on its input?
The 74LVC1GU04 is an unbuffered inverter, which (according to the datasheet) is intended to be used in linear mode in applications, such as crystal oscillators and linear amplifiers with negative ...
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Trouble with FSM circuit using Schmitt trigger clock
I'm having some trouble with my circuit based on the design below, that I built for the lab. I'm using a Schmitt trigger clock. I built the circuit on a breadboard and connected it to the clock and ...
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Jitter of schmitt trigger oscillator higher than expected
I implemented the following circuit on a pcb board.
The goal of the circuit is to measure the capacitance of C1 and C2 in a differential way.
C4 and C5 are the guards of C1 and C2.
The comparator ...
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D-type flip flop and Schmitt trigger [closed]
I've built a D-Type flip flop + Schmitt trigger to convert a momentary switch in a toggle switch using an SN74HC74N Dual D-Type Positive-Edge-Triggered Flip-Flops With Clear and Preset and a CD40106BE ...
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Simulate Schmitt trigger on Simulink
I'm trying to make the simplest circuit to see the Schmitt trigger behaviour on Simulink. I have the following circuit with the Schmitt trigger having the following options :
Low level input voltage : ...
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TTL Schmitt trigger vs TTL in relaxation oscillator
as far I know, the schematic works also with a simple TTL NOT gate.
Is there any special reason to use the Schmitt Triggers?
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Switching on an SSR on positive voltage and turn it off on negative voltage
I am currently trying to "hack" my way through a door lock, whose PCB cannot be changed. The task is to replace the motor for turning the cylinder with a Solid State Relay.
However, the only ...
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Suitable IC for 3.3 V to 5 V level conversion with a Schmitt trigger input [closed]
I've managed to find some ICs which enable level shifting, but none of them have Schmitt trigger inputs. In order to reduce cost and component count, I'd like to ask some of you experienced designers ...
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Square wave RL oscillator
So, I found this nifty oscillator & have been playing with it to generate square waves:
https://drive.google.com/file/d/1HfyMNSJ3phSvn3KAczzim-cAPSgw-3Rp/view (Ctrl+S on the text view)
As far as ...
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