Questions tagged [comparator]

A comparator compares two voltages or currents and switches an output to indicate which is larger.

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32 views

Operating Point of CMOS Folded Cascode Differential Amplifier

Designing a pMOS folded cascode differential amplifier to be used as a comparator with input 'IN' and ground as the reference input. Now, there are tons of different architectures that one could use, ...
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54 views

How do I calculate the power consumption of the polarity detector circuit?

What method can I use to calculate the power consumption of this block? In the paper it's equal to 3 μW at 1.5 V. The datasheet of the piezo sensor. The datasheet of the MAX9119 comparator. Circuit:
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compare this two signal to create spwm pulses output

how to compare this signal using relation operator or using comparator compare this two signals to get output off spwm(sine pulse width modulation) PLEASE HELP ME CREATE IT
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72 views

“Voltage divider holds 37% of supply voltage at negative” wrong in textbook

In my textbook, it states that "the voltage divider of R3:R4 holds 37% of the supply voltage at negative". However, I think it should be 63%.
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Using LM393 For SLA Battery Management

I had an old 6V SLA battery laying around, so I thought that it would be a great exercise to design a Battery Management circuit for it. Is the following circuit, based on the LM393, sufficiently good ...
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88 views

In this window comparator, what is Vout in function of Vin?

I have this very basic window comparator and I want to get it's function of Vout in the positive alternation and the negative alternation. I know how to do it when I have a normal comparator and its ...
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31 views

Method for connecting Unused comparator pins

I have a dual comparator and one of the comparators is not being used. I know with an op amp you're not supposed to connect the inputs directly to ground. The way I do it with op amps is with a ...
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2answers
36 views

Comparator logic control from a potentiometer

I'm trying to think of a solution to a problem. I plan to use a 10k linear fader to control a voltage controlled amplifier (THAT 2180), however I would like to be able to control a logic high and low ...
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46 views

Unable to connect amplifier output to comparator in opamp

I am amplifying a signal for a current transformer (CT) with an op amp. This amplified output signal I need to compare using op amp comparator. The supply voltage is 12V and the IC is an LM358. When I ...
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3answers
63 views

Thermocouple comparator choose

I measured the parameters of a thermocouple (R1). R1in=5 Ohm, V=1..10 mV (measured by multimetr). Ipositive = 5v/20000 = 0,25mА, and Upositive max = 0,25 * 0,001 * 100 = 25mV I have lm339, lm324. ...
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1answer
58 views

Comparator hysteresis input signal filter

I need to heavily low pass filter an input to a hysteresis comparator, but due to the fact that R1 is one of the components setting the hysteresis, I can't add additional RC-circuits in series with it....
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Building a 2 bit comparator tips and tricks with truth table

Build a 2-bit comparator using either two 74151 8-to-1 MUXs or two 3 to 8 binary decoders. Additional gates such as AND, NAND, OR, NOR, inverters can be used. So I got this question while coming ...
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Can someone help me understanding the working of 3-stage comparator/ discriminator, shown in attachment?

I am working on a project and I need a high DC gain comparator for it. M1,M2 are tge main differential amplifier and M1a, M2a are used for hysteresis. As per my understanding its a 3 stage comparator: ...
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418 views

What's the purpose of a diode to Vcc at an LM339 output?

I'm unable to figure out the purpose of this diode (1N4148) from the output of the comparator (LM339N) to VCC. It's not clamping anything as there's nothing that can pull that rail beyond VCC.
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51 views

Trigger relay at different voltages with voltage comparator

TL;DR - I need help on making a relay with voltage comparator which accepts two reference voltages. Aim My project needs to run a Raspberry Pi on solar power. Solar panel will be connected to a power ...
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1answer
42 views

NiMH battery pack charging circuit using Solar panel [Help]

Recently I have been working on a NiMH battery pack (7.2V / 2100mAh) charging circuit powered by a 12V solar panel. With some research I found charging NiMH takes different forms by measuring change ...
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96 views

Wiring a BJT differential amplifier in a circuit

I need to switch a 12V relay when an input signal passes a certain voltage threshold. I use this popular BJT amplifier: In my case: VCC = 5V ...
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2answers
136 views

Why can't a single-supply comparator handle negative inputs?

I tried simulating a basic comparator configuration in Proteus with only a single supply. The reference/trip-point is 2V. However when I simulated the DC transfer curve, all negative input voltages ...
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61 views

Photocell comparator circuit using LM339

How to prove this mathematically?
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2answers
83 views

Op-Amp Comparator Testing

I am having this op-amp Comparator. My circuit is similar to this circuit present in the datasheet of the IC, page 21. I have this circuit now in my board which I want to test. I have never tested an ...
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1answer
109 views

Oscillator circuit using comparator and opamps

All opamps are ideal and Rx = 2R in the figure. The comparator is a nonlinear block which operates as follows: if its input Va < 0, its output is +1V. If Va > 0, its output is -1V. To simplify ...
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2answers
103 views

Comparator simple build [closed]

So I was trying to learn about what comparators do and I did. They compare 2 voltages and if the voltage at the V+ pin is bigger than the voltage at the V- pin they output 1 else they output 0. Life ...
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1answer
78 views

IC design to amplify from microvolt to volt for making a comparator

I am developing an IC in CMOS technology which, among many other things, I need to compare one signal with another. I need a square wave signal above a limit to result in VDD, and signals below that ...
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152 views

Can a voltage comparator be constructed from NPN BPJ transistors and resisitors alone?

I'm working though some basic logic circuits with my niece and nephew and wanted to implement elements with transistors before we get more complex and replace modules with ICs. I know this is trivial ...
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64 views

What is the role of R1/C1, R3 in this slicer circuit?

I found the following data slicer circuit: simulate this circuit – Schematic created using CircuitLab The input is a simple NRZ (PAM-2) signal between "Vhigh" and "Vlow" (=...
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79 views

Overvoltage protection using opamp

This circuit is used for overvoltage protection, I can see that the two opamp are comparators that will output 0 or 5V depending on the input, but can't see how it is protecting from overvoltage. ...
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31 views

Comparator H Bridge current sense negative voltage input

I'm using lm339 basic comparator to sense current from an H Bridge. Current limiting was done somewhat successfully with acs712 after removing the capacitor from filter pin for limiting the bandwith. ...
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327 views

Custom 25 A mains inrush current limiter design review

I've designed an inrush current limiting circuit and would welcome a review from experts with more experience with this sort of thing. The load will be around 50 x 19 VDC @ 3.5 A linear power supplies ...
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1answer
57 views

Comparator have hysteresis with pull-up resistor?

I didn't add any hysteresis to below circuit but there's ~500 mV delay between output going high and low, output goes high at 7.5 V but goes low at 7 V: simulate this circuit – Schematic ...
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3answers
109 views

FET Written Inside Comparator/Op-Amp Symbol

I'm in the process of importing a bunch of old schematics from a 70's era synthesizer into KiCAD. In the process I've come across a symbol that I can't make sense of. It looks like this: Does anyone ...
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118 views

LM393 comparator is not working [duplicate]

I have shown output image description here in my Lm 393 comparator, my output is not coming proper square wave.picture is shown below.i have described my circuit. practically I am using voltage ...
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1answer
128 views

LM393 voltage comparator is not working

In my Lm 393 comparator, my output is not coming proper square wave.picture is shown below. I have described about my circuit. I am using voltage comparator LM393 for comparing two signals, one signal ...
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57 views

Despairing over uA741 as comparator

So, playing around with my first attempt at a circuit using an OpAmp, I am now simply in despair with these 741. Apparently they are "outdated" as any post even related to them is first ...
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1answer
46 views

MOSFET in LTspice sim conducts below the threshold voltage

Electronics noob here! I'm trying to create a circuit that feeds the output of a piezo transducer into a comparator, in order bring an arduino pin high when the piezo's output exceeds the comparator's ...
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126 views

op amps comparator or differential amplifier

I have a part of electronic schematic as described bellow, I'm a little bit confusing about the function of the LM321 amplifier. In this case, can we say that is a differential amplifier or just a ...
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68 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?
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33 views

Help understanding open collector comparator

I am working on a simple circuit based on the LM311 comparator. It has an open collector, which is not something that I've used before, and I have a few questions. First, my understanding of the open ...
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4answers
118 views

Understanding the operation of LM219 Comparator

I'm trying to use the LM219 (equivalently LM119 or LM319) comparator in a project I am working on (I chose this over other comparators because it has a fast response time for the desired supply ...
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1answer
179 views

Transistor differential comparator threshold

It seems that the circuit bellow acts as a differential comparator. I confirmed it by simulation on LTSpice. simulate this circuit – Schematic created using CircuitLab I remark that output ...
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1answer
176 views

Why does my comparator not compare?

I have designed a buck converter and I am baffled with its comparator's functionality. The op-amp comparator does not give a PWM, instead it gives an amplified ramp. What am I doing wrong?
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39 views

How to determine the value for the gate resistor (Rg) of a MOSFET in low side configuration?

Once the FSR is pressed the output of the comparator should go high. This, will drive the MOSFET ON which has a DC motor on its drain terminal. I was wondering how can I determine the value in ohms of ...
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1answer
32 views

Should I include a pull-up resistor for this application? simple schematic

Once the FSR is pressed the output of the comparator should go high. Since there is not really any "delicate" logic behind this schematic I was wondering if a pull-up resistor is really necessary for ...
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2answers
32 views

three points (two slopes) op amp conditioning circuit

I'd like to get the output on the right when applying the signal on the left to a signal conditioning circuit using op amps. I've got different slopes so I guess I need two amplifier circuits with ...
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49 views

Zero crossing detector using 311 comparator

Is the explanation correct? The output on positive voltage should be high and on negative voltage it should be low.
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26 views

Which comparator type to use as an On/Off switch for a DC motor via FSR (force sensing resistor)

I want to use an FSR (force sensing resistor) to turn on a 300-350mA (steady state) 4 volt DC motor while one press into the FSR. As the image shows my plan is to have a voltage divider between the ...
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2answers
53 views

Best practice when choosing a trim pot value

I have a basic comparator circuit I'm working on designing. I want one of the reference voltages to be tunable, so using a trim pot. My Vcc is 12V, so assuming a 1/4 watt pot, 1k seems like the lowest ...
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1answer
45 views

Is there a way to compare both signed and unsigned binary words?

By that I mean, is there a circuit that can compare two signed words against one another, but also be able to compare two unsiged words together, not comparing a signed word to an unsigned one. I am ...
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28 views

Low power consumption problem

I have a pressure sensor which is working in the feet of a person which senses the pressure. I'm using nRF processor for sending just ON/OFF signal to the motors. The problem is I'm using a battery ...
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4answers
85 views

Charge indicator with comparator - very sensitive to noise

I need an indicator when the current from my charger is larger than 100mA. I tried the below circuit but this seems very sensitivity to noise. Probably I am getting some ripple in the mV range from ...
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1answer
43 views

how the comparator amp works as integrated amplifier [closed]

I need some explain how does comparator work as zero cross detection and integrated amp

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