Questions tagged [comparator]

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

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55 views

Why TL071 Does'nt Act As a Comparator?

I am trying to obtain a square wave using a comparator and a sine wave signal. Sine wave has adjustable peak to peak amplitude with +10/-10 volts as limits. TL071 runs with +12/-12 volts. Sine wave ...
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57 views

Comparator circuit

I found this comparator circuit, the caption says "Self-Biased, 50% Slicer". Does this circuit output a logic high, when the input voltage is bigger than 2.5V and a logic low, when the input ...
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28 views

How to design a discrete flat-clamp TVS circuit

I need something similar to the Texas Instruments TVS3300 but for a higher voltage. The TVS3300 is basically a drop-in replacement for a TVS diode that clamps the voltage using an internal mosfet and ...
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CMOS latched comparator delay

This lecture presents an overview of ADC converters. In addition it discusses CMOS latched comparators and talks about various design issues. The author models the latched comparator as a single-pole ...
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109 views

How to prevent relay damage due to switching that is not smooth

I am driving a 9V relay from the output of a comparator (LDR sensor) and the relay gets damaged due to rapidly changing voltage from the comparator when light on the LDR is small. The relay starts ...
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29 views

Issues with delaying output on power on

I have two (and soon to be three) USB devices that need to be turned on sequentially, the first one being the "master" and the second one being the "slave". Since I don't want to ...
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72 views

opamp dc comparator [closed]

simulate this circuit – Schematic created using CircuitLab I am trying to compare the voltages of the inverting and non-inverting terminal but no matter what input I put in, the voltages seem to ...
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28 views

Analog comparator ATMega164

I am using an ATMega164 chip and the circuit below On D5 and D6 I have connected the pins of a DC motor, which has to spin whenever the read voltage drops under a threshold. I read in the datasheet ...
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53 views

Improving this circuit from Texas Instruments note (inrush current)

this is an example circuit in this PDF from TI. (page 19, inrush current stuff) Description : In steady-state operation, Q1 is fully turned on and load current flows through the series sense ...
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67 views

I need help figuring out how an evaluation board for an op amp works

What I am trying to do: I have a special photo detector(nano-wire, operates at very low temp) that creates an output trigger pulse every time it detects a photon. This trigger pulse(see picture ...
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69 views

Precise multi-point over-temperature control using comparator

This circuit will (hopefully) send a signal to MCU if over-temperature is observed in any of the NTCs. Using LM339 as comparator, and a reference voltage (from TL431), assuming high precision for NTC ...
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60 views

Comparator with Hysteresis_Design Calculations

I need to design a comparator with Vih=1.3V and Vil=1.2V. Therefore hysteresis is 100mV. The circuit will be working on a 3.3V supply. During high state, the o/p of the comparator will be 3.3V and at ...
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41 views

Li-Ion charger using LM338 & LM358

I have followed this tutorial on building a basic Li-Ion charger for a single cell. I have the output from the LM338 set to 4.2 volts as described in the tutorial but dont seem to be able to get the ...
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179 views

Split voltage mystery

As I was designing a split voltage supply for an opamp supply, I thought that cutting one rail if the other rail wasn't at it's nominal voltage would be a good idea if I wanted a "good" ...
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28 views

Cycle-by-cycle current limiting with latching comparator

I am attempting to design a cycle-by-cycle current limiting circuit for a motor driver. Here is my circuit along with some notes to explain its intended operation: The latching comparator I plan on ...
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4 bit and 3 bit comparator with 2 bit comparator

Hello so I am newly learning Digital logic design and my professor just started design of functional modules. We did comparator circuits: 1 bit, 2 bit & 4 bit. We have also studied how to design 2 ...
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123 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 ...
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94 views

This LM311 powered LED is not activating properly

I am taking the tractive voltage and dividing it by a factor of about 20 and comparing it with the reference of 3V. If the tractive voltage is 80V, that should be divided to 4V and that is greater ...
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29 views

Working of Comparator and LED Driver pin function?

I have this LED Driver - A80604 I need to generate 30V for my LED Driver String for generating 300mA. My question 1 - Both pins ADIM and PWM seem to perform the same function? Both typically take in ...
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1answer
37 views

Differential and common mode over-range indicator for In-amp

I need some advice with differential and common-mode over-range indication. I have a device with In-amp and I would like to add a Led or buzzer for differential and common-mode over-range indication. ...
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91 views

Small AC-DC conversion/amplification

So essentially looking for the most efficient and effective way to take a 3V 50hz AC signal and convert it to an 11-33V DC signal (any voltage between 11 and 33 works for an input to embedded pc) . I ...
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Help Designing an Impact Detector for Raspberry Pi

I am trying to design a little game where you throw a baseball at a 3x3 grid of 24x18" polycarbonate panels (1/4" thick), and the game detects which of 9 panels is struck. I'm aware there ...
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228 views

Op- amp comparators and temperature dependent resistor

The circuit in Fig 1 consists of a temperature dependent resistor (TDR). Compute the: temperature at which the comparator will change state. 2)supply voltage required for a 40°C trip point in Figure ...
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68 views

LM311 overheating

I breadboarded the circuited below. Within seconds of operation, both the L7805 and LM311 start to overheat very badly. I tought it had something to do with the coupling capacitor or the AC signal so ...
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50 views

Op-amp input voltage gets clipped off

I'm trying to build a simple voltage comparator using LM324N. Here is the circuit: simulate this circuit – Schematic created using CircuitLab The strange thing that happens is that after apply ...
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1answer
40 views

Using analog comparators to get 2 different outputs depending on the input

I am trying to use analog comparators to get two different output voltages, 6V out when the input voltage is -8.5V <= Vin <= -2V and -3V out when the input voltage is -2V < Vin <= 9.5V. I ...
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76 views

How does the comparator in the NE555 compare its two inputs?

This is a circuit diagram from the very detailed and helpful NE555 Wiki page. The yellow and red coloured segments are comparators, comparing Thresh and Trig to fractions of Vcc. If I know how a ...
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131 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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88 views

Making a light detector using a phototransistor and an open drain comparator

I want to make a light detector using a phototransistor. To do that I connected a phototransistor and apotentiometer to the open drain comparator as in the diagram below. When the light is dim, ...
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27 views

What's the small signal model of this CMOS differential pair?

I cannot derive the small-signal model for this differential pair: My goal is to observe the effect of transistors M6 and M7 which should create a hysteresis effect in the output equation for Vo1 or ...
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67 views

How about this design of analog comparator? [closed]

These day I design some transistor logic circuit for the high voltage sensing. I complete other necessary logic gate but, I didn't decide comparator circuit yet. Are there any improvements to this ...
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1answer
34 views

Sensor Signal Open-Circuit/Short-Circuit Faults — Trigger Shutdown Circuit

I am working on a project where I use the signal from 2 sensors in order to determine whether I want to trigger a timer circuit that then propagates a signal to latch an LED. The sensors give voltage ...
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30 views

Beginner Question: Get 2 Reference Voltages for Comparator using Voltage Regulators

I'm working on a project where I have a 12 V voltage supply. I need reference voltages of 4.5 V and 3 V which will be each be used as the Vref for a comparator. I am aware that I shouldn't use a ...
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74 views

OpAmp/Comparator for AC current detector circuit

I am trying to complete schematic for current detector. This is addition on How to build AC current sensor circuit for ESP-01 GPIO. By googling and researching I came with following schematic which I ...
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88 views

Need help to correct circuit

I am using this circuit to detect whether or not electricity is being consumed. There are two sensor sources (CT1 & CT2 ) where a CT coil will be installed. When electricity passes through that ...
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79 views

IR sensors not working in sunlight

I am using an ITR20001/t optical sensor for a no-touch application. It is working properly indoors, but if I put the setup in sunlight the IR receiver is enabling automatically. How can I overcome ...
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58 views

LM393 Ref voltage does not seem to work

I am trying to build a comparator using the LM 393. Just a basic design where I my Vref 3V is produced by 100/150 Ohm voltage divider. The input signal is a pulse from a geiger sensor as below: ...
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Is bandwidth of cmos comparator important?

The concept of bandwidth is developed based on small-signal analysis. However, comparator works usually under large-signal conditions, and transistors are not in saturation region, since comparator ...
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72 views

Op-Amp dynamic hysteresis

What is dynamic hysteresis in Op-Amp? I read section 4.3 of the this App Note and was not clear. Can someone explain me why this is happening?
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Circuit question for LM358 and NE555

I have made an IR proximity sensor which works fine when an LED is connected. Figure 1: This is the IR receiver and emitter part of the circuit. The white LED is connected to ground via a 270 ohm ...
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51 views

Am I using this LM393A comparator incorrectly?

I've read about comparators and from my understanding, you've got 2 voltage inputs: reference voltage usually connected at the inverting input and Vin i.e. voltage you want measured usually connected ...
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83 views

LVDS comparator re-triggers on falling edge

I have a problem with a simple comparator circuit. The comparator takes a 1 PPS (pulse-per-second) signal as a single-ended input, and outputs an LVDS signal. The issue is that the comparator, ...
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121 views

Comparator as operational amplifier

Using an operational amplifier as a comparator was asked quite a lot times here, but how does it behave the way around? I've a really cheap one in my circuit with low hysteresis and a MOSFETt push/...
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175 views

LM339 comparator trigger SR latch

In this circuit we have a LM339 comparator which compares input signal with respect to the threshold value which is 4 volts. This is the output of the transient analysis. If the input signal is ...
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124 views

Why does my LM311 comparator's output seem to be inverted?

From what I understand, the potential difference between its output pin (COL OUT) and GND is equal to the voltage of source when the potential of IN+ (pin 2) is greater than IN- (pin3). The opposite ...
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60 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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56 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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78 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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89 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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