Questions tagged [schmitt-trigger]
Anything related to Schmitt trigger circuits. Schmitt triggers are positive feedback comparator circuits exhibiting hysteresis.
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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 ...
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0answers
61 views
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 "...
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2answers
57 views
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 ...
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2answers
53 views
Problem in sensor circuit using a Phototransistor for the Schmitt Trigger circuit
This is my Schmitt Trigger design, which trips at \$2.3V\$ and \$1.7V\$-
Here,
$$+V_{cc} = 9V$$
$$R1 = 51k \Omega$$
$$R2 = 22k \Omega$$
$$R3 = 330k \Omega$$
\$V_{in}\$ is a square-wave with 0-7V peak ...
0
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1answer
69 views
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 ...
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3answers
69 views
Inverting Schmitt trigger design with subtle changes to the hysteresis loop and tripping voltages
Currently, I'm trying to analyze a Schmitt trigger circuit using the 741 IC op-amp, and how it overcomes the problems faced by an open loop comparator circuit.
This is a typical positive feedback ...
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1answer
42 views
Schmitt Trigger CD40106 has 5V at input with nothing connected
I am using Schmitt Trigger CD40106BE to make an PWM oscillator with controllable duty cycles. The schematic is shown below:
However, the LED that should be blinking is constantly on. After some ...
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1answer
86 views
Why is Vout less than Vcc here in a way disproportionate to beta? [closed]
Given: Vcc=9V, duty cycle = 0.5, oscillation frequency=500Hz
Note that I am not interested in electronics in any way (I'm planning to continue as a web developer yet need to finish my CCE major) so I ...
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2answers
102 views
Converting latching switch to momentary output
I'm trying to get a latch switch to send a pulse for around 3 seconds or so. The pulse doesn't need to be pretty or precise. The circuit will be used to sound a buzzer when the switch is flipped on. ...
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votes
2answers
77 views
Ideal v. Non-Ideal (?) Schmitt Trigger Transfer Curve
I was doing an assignment about op amps and I had to simulate a Schmitt Trigger and plot its transfer curve. The assignment handout gave me a plot to compare the curve with. Here are both the plots, ...
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0answers
70 views
What is the output of the integrator? How do I find the frequency? Op-amp integrator+Schmitt trigger
This is the circuit:
Integrator analysis:
From this formula I don´t know how to get the frequency. (I don't know if this is right, but I think it is.)
I found a website that says the frequency is R3/...
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vote
1answer
110 views
BC639 16 exploding on custom design
On a board I designed, a transistor, BC639 16, is exploding.
A pinball machine has one board that has some design flaws. Its schematics are these:
This PCB has 8 optos (QVE11233.0086) that are ...
0
votes
1answer
81 views
Understanding the Schmitt trigger circuit using CMOS inverters
This is the circuit I'm trying to understand:
What I understand:
Clearly, whenever \$V_{out}\$ is low \$M_{3}\$ is off and the strength of \$M_{2}\$ and \$M_{4}\$ surpasses that of \$M_{1}\$ so the ...
0
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1answer
87 views
Design a triangular wave generator using a sinusoidal input
I've been going through online assignments regarding circuit designs. I've gotten a bit stuck on this one:
Using a sinusoidal input voltage of amplitude 5 V and frequency 100 Hz, I need a triangular ...
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0answers
49 views
Do I need a separate capacitor bypass for 74xx14 Schmitt Trigger sharing power with Op Amp? [duplicate]
Do I need a separate capacitor bypass (network) for 74xx14 Schmitt Trigger sharing power with Op Amp?
Power supply is 500mA but entire circuit is using around 70-80mA. And sub-circuit with OP AMP + ...
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2answers
72 views
Control multiple Schmitt Trigger oscillators from a single current sink
I'm playing with an idea for a VCO (Voltage Controlled Oscillator), and would like to make something a bit out of the ordinary. My idea is to run multiple sawtooth oscillators from a single control ...
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1answer
87 views
Schmitt trigger VS transistor [closed]
Can you please explain for me what is the difference between Schmitt trigger and transistor, especially in driving LEDs and in current consumption.
EDIT: There's answers and comments which seem to be ...
4
votes
2answers
213 views
In an astable multivibrator, why doesn't negative feedback prevent the output from ever saturating?
What I understand of an astable multivibrator so far is this:
The output saturates to one of two extremes, which drives the capacitor in the negative feedback loop to either charge or discharge.
Once ...
4
votes
2answers
167 views
I am facing a problem while designing a Schmitt trigger circuit
I am applying a Schmitt-trigger to the waveform given in the figure below.
.
This is a 3.5 volt signal and I want to perform thresholding so I use 1.58 volts as upper threshold and 1.17 volts as lower ...
0
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1answer
81 views
RC circuit and HEX SCHMITT-TRIGGER INVERTERS
I have a complex circuit, and I am dealing with a problem that appears. I have a RC circuit followed by
a 7414 Trigger inverter. My input voltage is 90mV and after the simulation the output looks like ...
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1answer
95 views
using Schmitt trigger to debounce a switch [closed]
How can a Schmitt trigger be used to debounce a switch? please try to explain it with pictures as well.
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1answer
59 views
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 ...
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0answers
29 views
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 ...
0
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2answers
159 views
Initial condition of Schmitt Trigger Circuit
I am trying to understand working of the following circuit;
It has Input from 0 to 7V and based on the Input value Output A to D will be High or Low but ...
Is it Inverting Schmitt Trigger ...
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1answer
65 views
Schmitt trigger inverter not properly outputting 5V
In my project I'm working on right now, I'm trying to use a Schmitt trigger inverter to help debounce input signals. Below is my overall circuit I am trying to implement:
The Schmitt trigger inverter ...
0
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1answer
65 views
Schmitt trigger low threshold calculation
I have this classical Schmitt trigger circuit from an old Elektor magazine.
It describes the following, when U1 is lowered (from a high state):
If the right transistor cuts off entirely and the left ...
4
votes
3answers
543 views
Minimizing signal delay when debouncing
I have a mechanical switch that I'd like to use as a signal source for a digital input of a microcontroller. The switch is normally closed, and I'd like to detect the switch being opened as quickly as ...
0
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5answers
941 views
Can we declare Schmitt triggers to have memory? Can we call their output levels states? [closed]
Are Schmitt triggers able to be declared as having memory? Can we call their output
levels states?
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1answer
57 views
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 ...
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0answers
76 views
Why is it necessary to use a voltage limiter at the output port of a Schmitt trigger?
Why is it necessary to use a voltage limiter at the output port of a Schmitt trigger? How are switching thresholds determined in various types of Schmitt triggers?
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2answers
352 views
I need help debouncing a push button
I am trying to debounce a button.
Here is my result so far after placing a 1uF ceramic capacitor in parallel with the button:
This should work as an input to my Arduino 5V since it has High: U >= ...
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3answers
386 views
Why doesn't the following circuit have negative feedback?
Consider:
The Sedra book says that it's a Schmitt trigger, so there is positive feedback, but why doesn't it have negative feedback as well?
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0answers
76 views
3.3V to 15V PWM converter
I have the good old problem of converting a 3.3V logic voltage to a higher voltage.
Higher means everything between 12 and 20V. With 15V being used most of the time.
The highest frequency I use now is ...
1
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1answer
62 views
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 ...
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2answers
150 views
Schmitt trigger not working
I have a circuit like this:
I am using a LT1719 for the Schmitt trigger. The Schmitt input signal is intended to be a 6 kHz waveform of 0.6 V pk-pk amplitude.
When I test the Schmitt with an ...
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2answers
57 views
Design review for photoresistor-controlled linear regulator
I would appreciate some comments/insights/criticism on my design:
I want to turn on/off a linear regulator (MIC5504) based on the light. I have tried just using a resistor and photoresistor voltage ...
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0answers
139 views
Solar-powered 74HC14 LED flasher: oscillators interfere
I am building a "nocturnal solar engine" with two LEDs flashing independently, following the description at the old Solarbotics website. I am essentially rebuilding the same circuit. The ...
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0answers
40 views
How to create timing waveforms for an H-Bridge Inverter
This is my first question on Stack Exchange.
I am in the process of simulating a wireless charger coil setup on LTSpice. I have tried a Royer/Baxandall oscillator to provide the necessary sinusoidal ...
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0answers
58 views
Schmitt Trigger voltage divider
Could someone please explain to me when and why should we add a voltage divider at the inverting input of a Schmidtt Trigger?
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5answers
788 views
High Frequency Square Wave Generator
I want to generate square wave but there are some challenges. Rise time should be less than 2ns as well as fall time (for 0V to 5V). Duty cycle is not so important it should stay high like 40 ns. I am ...
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2answers
279 views
Hardware debouncing using 74LS14 - inverter input does not drop below 800 mV
I just recently started dabbling with electronics, so probably I just made some beginner's mistake. Here's my problem: I want to debounce a switch in hardware. During my internet research, I found ...
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1answer
208 views
How to use op-amp circuit as a threshold trigger
I recently built the following circuit:
In case you can't tell, it has 23 volts on the power rail and VEE is connected to ground. I don't have any feedback on the output. I have a simple voltage ...
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votes
4answers
952 views
Why is this derivation of Schmitt trigger circuit's output signal, incorrect?
This is the reference Schmitt trigger circuit. Using KVL, \$V_x\$ turns out to be \$\frac{R_1}{R_1+R_2}V_o\$. Also,
$$V_o = A\left( V_x - V_i\right)$$
$$V_o = A\left( \frac{R_1}{R_1+R_2}V_o - V_i\...
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0answers
115 views
Schmitt trigger output waveform coming as sinewave
I am new to Proteus. I tried simulating an easy circuit which was a Schmitt trigger using an op-amp.
After simulation, the output waveform was an sinewave instead of rectangular wave.
Any idea where I ...
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4answers
362 views
Push button de-bouncing, nothing works. [Please, only answer if you have actually done it (recently or often enough) to know for sure!]
I see a lot of text on the internet and here telling us how to de-bounce a switch, in my case a push button. But I have tried all these circuits and I find that nothing other than a 555 monostable ...
0
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3answers
260 views
Positive edge detection triggers on negative edge too
I have 74LS170s and 74LS670 register files which have the trouble that they are not edge triggered but like SRAM accept data for the entire duration of the write gate being low.
So, I have the ...
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0answers
70 views
DC Supply voltage drop in a Schmitt trigger circuit
I developed a Schmitt trigger using IC NE555P. I supplied a Vcc of +6v from a DC source. My input is a sinusoidal wave (peak-peak = 4V). First I set the voltage in DC source (+6v) and when I connect ...
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0answers
78 views
Schmitt trigger using NE555P gives wrong output
I am trying to create a Schmitt trigger using NE555P to generate square pulses from some periodically changing signals. I used the following circuit diagram and applied some sinusoidal waves (3.3v). ...
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1answer
72 views
Anyway to reduce pulse trigger time width without using ne555timer [closed]
Is there any other way to reduce the time width of the trigger pulse wave without using 555timer?
