Questions tagged [schmitt-trigger]

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

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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 ...
Organ Bender's user avatar
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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 ...
Emerson's user avatar
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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, ...
Dale Woods's user avatar
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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 ...
radiolite's user avatar
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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
Saiful's user avatar
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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 ...
Muhammad Nour's user avatar
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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 ...
Khales Naim's user avatar
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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 ...
MAJID AHMAD's user avatar
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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 ...
maher471's user avatar
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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 ...
eaterbugs's user avatar
2 votes
3 answers
171 views

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. ...
c.leblanc's user avatar
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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, ...
Jina's user avatar
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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: $$f=\frac{1}{2R_4C_1\ln(3)}$$ ...
ronny's user avatar
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4 answers
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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 ...
Jason's user avatar
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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 ...
bittscoterie's user avatar
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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 ...
Chris's user avatar
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2 answers
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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 ...
M4Biz's user avatar
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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 : ...
Hibou's user avatar
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2 votes
3 answers
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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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6 votes
2 answers
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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 ...
Sofia Braun's user avatar
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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 ...
Phill Donn's user avatar
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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 ...
Tempus Nomen's user avatar
2 votes
1 answer
3k views

Schmitt trigger Upper and Lower Threshold voltages

I speak with reference to this (Electrical4u - blog tutorial) and this (All about electronics - video tutorial) on the Schmitt trigger. From what I have understood, in the non-inverting schmitt ...
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How does the CMOS Schmitt trigger work

I have some questions on how the schmitt trigger works. Assuming we start with low Vin hence Vout is high. It means that M1 is ON thus the source of M2 is conducting Vdd hence M2 is On as well. ...
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SPDT switch with opposite polarity and bounce eliminator/debouncer with Schmitt Trigger

I had a question in my electronics course homework pertaining to eliminating the bounce from a SPDT switch with a Schmitt trigger. The switch has two inputs with opposite polarity. I've looked online ...
imthegman55's user avatar
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What is the purpose of a negative feedback resistor in a schmitt trigger?

This schmitt trigger is used with an integrator to create a triangle/square wave oscillator but R5 has been added to the typical inverting schmitt trigger topology. I know that in simulation, this ...
Jeb Kerman's user avatar
4 votes
5 answers
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How to fix oscillation of an 'over-discharge protection' circuit for a lead-acid battery

I've created a circuit to protect my lead-acid battery from over-discharging. I used the following circuit diagram. Over-discharge protection circuit for a lead acid battery: For understandable ...
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CD4069 toggle switch

How to connect the trigger out instead of the switch? Like a toggle switch. The first trigger out activates the relay and remains ON infinity, the second trigger out deactivates the relay and remains ...
Smekeri BezPrezimena's user avatar
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2 answers
315 views

Schmitt Trigger Circuit Output Rise Time

I'm just working on a basic Schmitt trigger circuit. But I have a question about the rise time of Q3. As shown in figure the collector fall is very sharp, but on the other hand when the transistor ...
analog_designer's user avatar
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Fan-Out Calculation on LTSpice

I need to find the fan-out of the circuit below. This is a Schmitt Trigger TTL NAND Gate. How can I exactly find the fan-out of the given circuit using LTSpice or calculate it theoretically?
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How to calculate RC values according to threshold points of a Schmitt trigger inverting oscillator [updated]

I'm trying to make a high-period, low duty cycle signal to trigger a regulator (EN pin) for lower power consumption. I tried to simulate this simple circuit in various simulation software, using "...
Tirdad Sadri Nejad's user avatar

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