Questions tagged [schmitt-trigger]
Anything related to Schmitt trigger circuits. Schmitt triggers are positive feedback comparator circuits exhibiting hysteresis.
243
questions
0
votes
0
answers
15
views
LTspice to PSIM
I was trying to construct the circuit of UC3843 on PSIM and stumbled across a useful circuit created in LTspice. Now I am confused about these circuit symbols and what they represent:
At first glance,...
- 11
2
votes
3
answers
57
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. ...
- 191
0
votes
1
answer
83
views
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, ...
- 81
0
votes
0
answers
27
views
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.)
...
- 83
2
votes
3
answers
678
views
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:
$$f=\frac{1}{2R_4C_1\ln(3)}$$
...
- 83
2
votes
4
answers
101
views
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 ...
- 31
8
votes
1
answer
496
views
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 ...
- 5,287
0
votes
1
answer
51
views
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 ...
0
votes
0
answers
62
views
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 ...
- 1
1
vote
2
answers
98
views
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 ...
- 339
0
votes
1
answer
73
views
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 : ...
- 101
2
votes
3
answers
233
views
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?
- 185
6
votes
2
answers
248
views
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 ...
- 73
0
votes
1
answer
165
views
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 ...
- 335
0
votes
0
answers
62
views
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 ...
- 343
2
votes
1
answer
778
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 ...
- 23
0
votes
0
answers
397
views
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. ...
- 7
0
votes
1
answer
74
views
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 ...
- 105
0
votes
0
answers
111
views
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 ...
4
votes
3
answers
619
views
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 ...
- 726
0
votes
0
answers
210
views
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 ...
0
votes
2
answers
223
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 ...
- 145
0
votes
0
answers
439
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?
- 3
0
votes
0
answers
82
views
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 "...
- 1,703
0
votes
2
answers
127
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 ...
- 399
0
votes
2
answers
197
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 ...
- 41
0
votes
1
answer
137
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 ...
- 41
1
vote
3
answers
228
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 ...
- 41
1
vote
1
answer
273
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 ...
- 171
-1
votes
1
answer
220
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 ...
- 11
0
votes
2
answers
870
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. ...
2
votes
2
answers
134
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, ...
0
votes
0
answers
154
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/...
1
vote
1
answer
118
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
1
answer
406
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 ...
- 297
0
votes
1
answer
270
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 ...
- 121
1
vote
0
answers
52
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 + ...
- 135
0
votes
2
answers
224
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 ...
- 195
-3
votes
1
answer
132
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 ...
- 3
4
votes
2
answers
321
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
2
answers
271
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
votes
1
answer
170
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 ...
- 21
-1
votes
1
answer
1k
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.
0
votes
1
answer
74
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 ...
- 533
0
votes
0
answers
44
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
votes
2
answers
233
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 ...
0
votes
1
answer
99
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 ...
- 113
0
votes
1
answer
153
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 ...
- 131
4
votes
3
answers
616
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 ...
- 392
0
votes
5
answers
1k
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?
- 33