Questions tagged [comparator]

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

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37 views

single photon counting circuit using amplifier/comparator

My goal is to design a single photon counting circuit using some wide-bandwidth, low noise amplifiers and a comparator. Based on the available parts on Ebay, I used a silicon bipolar MMIC amplifier ...
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53 views

LTspice subcircuit with behavioral voltage source

I'd like to use behavioral voltage source in subcircuit block, as showed below: With block "comp": But when I try to simulate it doesn't work and gives mi this message: Someone could explain what's ...
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35 views

Comparator problems with output

I am kinda new to electronics design and I am having some trouble with the Analog Devices LT319AN chip. I am trying to do simple 250KHz PWM which worked on a lesser LM393 chip in this exact setup. I ...
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61 views

Determine the voltage at which the comparator output switches from 0V to 10V

I have the following problem: Consider the circuit below Assume that Vo = 0 V, and that Vin slowly increases. At what value of Vin does Vo switch from 0V to 10V? I'm not sure how to ...
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69 views

LM393 comparator only connects to GND

I'm testing out the comparator LM393 but when I try and the comparator conditions meet it only outputs low and won't switch high. That or I don't understand how it works properly so if you can help ...
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46 views

An Opamp Comparator Design I made

I tried to come up with a design where if the input voltage is bigger than -8 volts the output will be input, if smaller than -8 volts it will be grounded. I ran the simulation on LTSpice and it works ...
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96 views

Unknown 5-pin opamp / comparator IC with “>10” marking

I'm trying to figure out what this 5-pin IC from the below image could be: The SMD Package looks to be TSSOP5. The component is used in the Kemet SS-430 sensor module. I think, is part of the output ...
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40 views

Strange powering of the TL710 comparator

I have an old schematics of 80th fancy synthesizer VCO. It uses the TL710 comparator, that according to the datasheet has -7V Negative Supply Voltage. I cant find the emitter-base breakdown voltage ...
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820 views

Can LM339 comparator inputs go way above Vcc?

The datasheet for the LM339 quad open-drain comparator shows the absolute max values: \$V_{cc} \le 36V\$ (Supply voltage) \$V_{I} \le 36V\$ (Input voltage range (either input)) I want to compare a (...
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2answers
68 views

Op-Amp comparator output not reaching 0V

I am using a UA741CP opamp IC as a simple opamp voltage comparator. I initially supplied it with 5V and tested the circuit as shown but even though I give voltage less than inverting input to non-...
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76 views

Trying to detect if a battery is charged

So I am doing a project as part of which I have rechargeable 5V battery and a charging source. I want to detect if the battery is charged and if it is then all the current should flow to a dummy load ...
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32 views

Regulated input relay switch

simulate this circuit – Schematic created using CircuitLab The control input may vary. What I want is, the relay will only switched on if the input voltage on R1 is at least 5 V. It works but ...
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211 views

LM393 comparator how to use?

Update: All I want is, when the signal is higher than reference voltage, LEDs to light up(brightly). For this, I was planning to use an op-amp as comparator (left circuit) but everybody told me to ...
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54 views

Compare tiny capacitance using comparator [duplicate]

I want to compare the capacitance of two tiny capacitors at around 10^-15 F each. One will change compared to the other by at maximum factor 3. I need to measure the relative difference between them ...
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206 views

What is the purpose of resistor?

LM311 datasheet, page 18: Is it a hysteresis so that when transistor opens, the reference voltage goes up? Or is it related to input signal filtering (then what is the corner frequency?). Can you ...
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53 views

Comparing voltages bigger than V+ on LM311

I want to use an LM311 comparator to compare my 12V battery voltage to some reference I have, but I want it to output 5V so I can read it with my microcontroller. Due to this, I'd think I have to set ...
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60 views

Voltage at comparator entrances

I have the following problem. I have to fill in the blank spots in the picture below. I'm not sure how to answer this question. My book just says: If \$V_+ > V_-\$ then \$ V_{out}=max\$ If \$...
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156 views

How does this overcurrent detection circuit work?

This is a overcurrent protection circuit. It'll triggered when it's more than 2Amps. I'm wondering how does that LM339 works related to the circuit. On the datasheet of LM339 page 11-13, it says: – ...
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86 views

How does the comparator work internally?

I'm currently working on LM339 comparator. It says "If IN– is lower than IN+ and the offset voltage, the output is high impedance" on the datasheet. I'm wondering how does the comparator makes it go ...
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19 views

Op amp Type 2 Compensator with Uc3845

I came across this type of compensator to connect to UC3845 with 2 diodes (D3-D4). Why those diodes connect there? Is it necessary to put them? I have attached shematic.
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3k views

Is there any reason as to why the schematic symbol of comparators is almost equivalent to that of op amps?

They do similar tasks, but they are almost completely different because comparators output digital signals. In that case, I am confused as to why their schematic symbol is almost entirely the same. Is ...
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30 views

Input Voltage of Comparator (Derivation)

I am trying to derive the voltage Vx, in terms of Vin, C, Cp, Voff, and finite gain Av of the op-amp at the end of phase 1, and then again at the end of phase 2. I am getting thrown by the direct ...
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33 views

Timer/Counter Compare match event fired on next clock tick

I'm using ATmega2560's timer-counter3 to count external pulses. I need to switch some output pin to logical 1, wait for some amount of input pulses at T3 pin and then immediately disable output. I've ...
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2k views

Very high precision zero crossing detection

I have a setup that is equivalent to a guitar string with pickup, with signals of similar frequency range. I have a simple zero crossing detector with a comparator and then just count the interval ...
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49 views

Comparing the results of two electronic dice

I made two electronic circuits each consisting of a 555 Timer, a CD4017 and 7 leds in the shape of what you'd find on a dice. They work great and all, but I want to "compare" the results of both and ...
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28 views

LT1721 pulse generator manual gives unexpected resistor values?

I've designed a circuit depending mostly on this LT1721 pulse generator, that's been thought up by the nice people at Analog: https://www.analog.com/en/design-center/reference-designs/circuit-...
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How to create the UVLO hysteresis in energy harvesting design?

I had try LTC3588-1, BQ25570 in my project. Both of them have a UVLO function. For LCT3588-1, if choosing 1.8V output, the output will be opened once the voltage of the storage capacitor reach 4V. The ...
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56 views

How to simulate flip flop noise

Or is flip flop noisy at all? would you simluate its noise as you would do with a strong arm comparator? Why is strong arm comparator noisy but not a flip flop?
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1answer
40 views

Using a compartator to make an LED light up. How do I make the LED light up?

This is my circuit that lights up an LED for less than 4 seconds of volts using 4V. How do I make the LED light up? I thought the output of the comparator was the comparators supply voltage, and that ...
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1answer
43 views

A circuit with a non-inverting op-amp and comparator for amplifying the output of a piezo transducer. Am I missing anything?

I'm a total noob when it comes to electronics so was hoping some people might be able to take a look at my circuit and see if it makes sense. I'm trying to create a circuit which amplifies the puny ...
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1answer
33 views

TLC372 comparator setup

I am using a comparator Model TLC372CP in following setup: As the TLC has two comparators included, I am just using one of them. If I am using the potentiometer, I can measure a dropping resistance ...
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65 views

How can I improve this digital-output / digital input (automotive)

I'm creating some circuits required in a student-built electric-vehicle application. There are no heavy loads on the low-voltage +12V system. What I have below is a circuit that does some threshold ...
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630 views

Output of LM393 won't swing LOW unless it is pulled up with a LED

I built the following circuit using an LM393 as part of a noise gate for audio applications. It's a voltage comparator with hysteresis. I originally connected a 10 kΩ pull-up resistor and then ...
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68 views

Window comparator diode direction

What happens if we reverse the configuration of diode in window comparator? Will it remain a window comparator?
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1answer
62 views

What does a comparator consume compared to an ADC

Is there a way to calculate the power consumption of a comparator for one single measurement? I would like to compare the power consumption of a comparator with the power consumption of an ADC. I ...
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1answer
65 views

Circuit with dual power supply

Doing some reverse engineering to a PCB, I drew this part of the circuit. Looking into the datasheets, I found out the comparator (LMC6772) is able to drive the SCR (S6S2) by itself. But the designer ...
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83 views

Why aren’t the magnitude comparators cascaded the “more efficient” way?

In Practical Electronics for Inventors, Paul shows the following cascading of two \$ 74HC85 \$’s to build an 8-bit magnitude comparator. Question: Why doesn’t he cascade them in the apparently more ...
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76 views

LM339 Lipo Battery Voltage Tester Circuit - How does it work?

After reviewing the eevblog video on OpAmps and various other videos on the LM339, as well as copying a circuit which works, I am still genuinely confused on the math / logic behind this, which makes ...
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72 views

Operation amplifier circuit input potential [closed]

How do you find the potential at A and B? I'm a bit confused.
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1answer
74 views

Square wave input to Comparator gives a weird output [closed]

I am designing a comparator whose input is a square wave with following spec Low=1.6V and High=2V. The reference of the comparator is placed in that range, in particular, REFH=1.282, REFL=1.182  ...
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88 views

comparator opamps & AND gate

I have two comparator opamps which connected AND gate. I would like to change the output of the AND gate by changing the voltage on the 5k resistor with the Potentiometer. I increased potentiometer ...
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2answers
90 views

discrete triangle generator

I am trying to design a convertor from analog to PWM with very good THD as in this http://www.ti.com/lit/ug/slau508/slau508.pdf The triangle generator (fig 2) (I am trying for 750Khz to 1Mhz) is a ...
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1answer
99 views

Understanding Self Power Supply

I took the circuit below from an App Note from Texas Instruments, and I decided to study it. My questions are about the comparators U6A, U6B. About U6A: The inverting input is set to 0.7 V because ...
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167 views

Why is this potentiometer and comparator circuit not working?

I'm quite new to electronics and I'm afraid I'm missing some basic knowledge. (also please forgive me if I'm not always using the right terminology) I'm trying to use a potentiometer (R1 in the ...
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1answer
85 views

Understanding this comparator circuit

This is what I understand about the circuit: It's not a window comparator exactly as the outputs are not connected together and the inverting inputs are actually connected together. They look like ...
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1answer
31 views

AD790JNZ constant high output

I am using a AD790JNZ comparator and am always getting a high output regardless of the input. It is connected as in the image below and is powered by a single 5V - 0V. When +In is greater than -IN the ...
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1answer
216 views

Is this a reasonable, robust way for detecting voltage crossing a threshold?

Updated, functional design at the bottom of this question I wish to detect when a low-impedance signal is below or above 60VDC (±3V). When the signal is above 60V, I'd like to indicate this by ...
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66 views

Basic OpAmp as a Comparator question

I'm continuing my refresher on electronics, and want to validate a conclusion/deduction that I'm reaching. Consider the two comparator circuits below: In both cases: I have chosen not to picture ...
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64 views

MAX999 draws current through negative input

I have two versions of the input signal: 5V inactive level, 3.2V active; 5V inactive level, 0V active level. Thinking on making universal circuit to support both signals, I decided to use comparator,...
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1answer
34 views

Comparator with hysteresis for bus-powered communication

I have a circuit that, supposedly, converts a current-modulation signal to a digital signal. This is basically the receiver end of a bus-powered, bi-directional serial communication device (master). ...