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Questions tagged [comparator]

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

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3answers
129 views

Detecting if specific signal is applied to circuit

I am doing a project and need to detect if a specific signal in the form of 2 + Asin(2πft) where A is between 1 and 4 and f is 20Hz - 20kHz. Once this id detected I will light an LED. I was thinking ...
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1answer
603 views

How to design a comparator using op-amp?

Intention is to design a comparator with following specification: Input: 0V to 1.65V, Output: Low Input: 2.1V to 5V, Output: High This is the TI design doc I have refereed for the design. Please ...
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1answer
4k views

designing a 3-bit comparator using only multiplexers

I need to design a 3 bit comparator using only multiplexers specifically 74ls153 and/or 74ls151. I've already constructed the truth table(see below) and realized that A=B is not needed since its ...
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2answers
239 views

Why use PWM signals?

Why, in a lot of applications (e.g for bioengineering where very small devices are developed for the recording of biosignals), after an amplifier there is a comparator (with two inputs, one for the ...
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1answer
368 views

Some questions about a comparator circuit used as a buffer

I want to hardware-trigger a module from a separate remote data-acquisition system's analog output. The module's hardware-trigger input is optically isolated to prevent grounding problems. And the ...
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2answers
588 views

Op-Amp as comparator for driving relay stops working after short time

Ok I have an Op-Amp as a comparator, Its the TCA0372... whole amp it can source, not needed just nice. and I have a relay, http://www.mouser.com/ds/2/315/jw-catalog-1075968.pdf Its driven by 12v. ...
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1answer
116 views

Comparator hystereris

Can someone help me to understand a little better how the hysteresis work in this circuit? I can understand the explanation below why VTRP- = vgs2-vgs1 = .... Also, I didn't find the meaning of the ...
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1answer
79 views

Comparator circuit undesirable fluctuations

I have designed a comparator with hysteresis and rail to rail operation and my output depicted in figure1.The inputs of the comparator is a sine wave signal and a triangular waveform as shown below....
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1answer
202 views

Comparator/capture miss during RC timing

I've written a capacitance meter for the Arduino Mega platform, which has an ATmega2560 chip. It works using a simple first-order RC charge circuit, and the ATmega's comparator, bandgap ref and time ...
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1answer
118 views

I wanna know how this comparator works [closed]

The diagram that is shown in the figure compares if the voltage supplied is higher than the reference voltage or not and the. Gives the output, high or low, accordingly... What I don't understand is ...
2
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1answer
389 views

MIC6270 comparator - input voltage higher than supply rail

I've read in various places (such as here) that you can't safely feed an input voltage to an op-amp / comparator that's above its supply voltage, even when within maximum ratings. However, the ...
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1answer
225 views

Help Comparator circuit

I would like to design a comparator circuit with hysteresis, which will provide a PWM signal in the output as shown in figure 2. The first input of the comparator circuit will be a sinusoidal signal ...
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0answers
45 views

MAX9032 comparator to drive an LED for TX line

I have got a MAX9032 dual comparator in one of the projects that I am working on and I have one spare comparator that I can use to drive an LED when the microcontroller is transferring the data to the ...
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1answer
131 views

Questions on interfacing circuit for an NPN input

I have to use this sinewave outputting sensor with the NPN input of this converter. My previous question was related to the same issue but the question was about a totally different circuit design i.e....
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0answers
114 views

Voltage offset on comparator

I want to make an ideal diode using a comparator and one p-channel mosfet. I'm looking for a cheapest method to add a few millivolts (25mV - 50mV) as an offset to one of op-amp's inputs just to ensure ...
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3answers
554 views

Can this comparator input exceed its supply voltage?

I will use this comparator with 12V DC single supply. Some of the pulse inputs to this comparator will exceed 12V that is to say the inputs to its inverting input can be up to 24V. So input voltage ...
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1answer
69 views

LT1711 maximum supply voltage and maximum input voltage

I want to include the LT17111 comparator into my design but I cannot get some clear information from the datasheet here. Can I power it from 12V and GND? Can I put a signal with 8V amplitude into one ...
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0answers
168 views

What MOSFET circuit replaces a diode in a 48V 40A escooter?

I want to use a 1kW generator and convert my eScooter to a hybrid. The scooter uses a 48V SLA battery bank of 4x22Ah SLA batteries in series. I used a transformer from a 1200W microwave oven and ...
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1answer
83 views

Resistance tester

I would need to create a simple tester with battery supply that compares resistance of specific wire with reference (approximately 4 ohms) and determines if the wanted resistance is in desired range. ...
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2answers
122 views

TINA simulation of TPS3701 Voltage Comparator output wrong

I am using TINA to design a voltage comparator, starting with the Typical Application of page 16 of the datasheet: When I run a transient analysis, the results are completely wrong, OUTA doesn't rise ...
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1answer
190 views

109 bit tree comparator with generate and for loop

I am trying to write Verilog code for a 109-bit tree comparator, but I am still new to the generate loop. I have written some code so far but I am not sure if this will work or if I can use 2-d ...
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4answers
566 views

Comparator Output Unstable

I have designed a comparator with hysteresis using LT1719. When I apply no signal, at op_amp_2, I expect the output to be high. However I see a sine wave at the output. This is the schematic of the ...
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2answers
1k views

Dynamic Braking resistor chopper circuit

I want to design a standalone dynamic braking circuit for AC motor driver , because to deal with regenerative energy that the AC source cannot handle causing a DC bus voltage Rise . The concept is ...
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2answers
49 views

Finding Alternate Comparator by Pinout?

I am using the TS391IYLT in a design, but need to swap it with an alternate that has rail-to-rail capabilities. The issue I'm running into is that the pinout is somewhat irregular; see below. Most ...
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1answer
791 views

Is there an 'analog' AND gate?

I'm also looking for some component that will have two inputs: the signal (call it pin A) and a reference (pin B). The reference will either be 0V or 1V/5V, so basically on/off. If B is on, then the ...
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2answers
280 views

How to stabilize the output square wave of a TL074CN (Comparator)

Figure 1 simulate this circuit – Schematic created using CircuitLab I am using a TL074CN comparator to compare a fullwave rectified input voltage with a DC voltage of 1.4 V as shown in the ...
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1answer
116 views

PWM signal is affected when motor is connected

I am working on a fun side project where I am creating a PWM waveform using the LM324 and a small solar panel. I am using the LM324 for the astable multivibrator, integrator, and comparator. The ...
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1answer
227 views

LTC4365 Over/Under voltage setpoints

I built the over and under voltage protection circuit based on the LTC4365 from the May 2017 QST page 32. Works ok. The LTC4365 uses an external resistor voltage divider to set the over and under ...
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3answers
1k views

How to create a zero crossing detector using a full bridge wave rectified circuit

Currently 1) I have a full bridge wave rectified ac waveform of 10Vmax. 2) I also have a potentiometer adjustable DC waveform. 3) My rail voltages are +12V and -12V. 4) I currently supply my full ...
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3answers
107 views

Detect ~500 uV change and output 3.3V?

I have a device that outputs 12.4 +/- 0.1 mV when it is inactive and 12.9 +/- 0.1 mV while it is collecting data. I would like to trigger another device that expects 3.3V high and 0V low for it's ...
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2answers
109 views

Wind turbine protection comparator circuit

I am trying to design a protection circuit for wind turbine. It suppose to stop turbine rotating when wind speed is to big. I came up with this circuit. simulate this circuit – Schematic ...
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1answer
402 views

Enable switch (transistor) at certain voltage with comparator

So right now I have a boost converter with a capacitor at the output as energy storage. My idea was to use a comparator (DC) comparing capacitor Voltage vs. reference, and the output was connected to ...
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0answers
68 views

Can the out-signal from MAX4173 be slowed down?

I have designed a small voltage / current monitor that works perfect in a lab-setup. However, when I yesterday tried it in the real application, it latches immediately. The only reason I can think of ...
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1answer
355 views

Why is this comparator loading down a voltage divider?

I just built up a circuit with a LM311P comparator with open collector and emitter (I don't think that's relevant). The negative input is a voltage I create with a voltage divider and the positive ...
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1answer
425 views

Purpose of capacitor in op amp feedback loop of power supply comparator

I've been analyzing the schematic for an old commercial linear power supply, the Farnell LT30/2 (schematic). The schematic contains a couple of examples of an op amp arrangement that seems very ...
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3answers
1k views

Schmitt trigger resistance

I was thrown off by a certain website while learning about a op amp Schmitt trigger design. The layout was the same inverting config as the above schematic but gave a confusing answer to calculating ...
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1answer
469 views

LM301 comparator and diodes on compensation

I'm trying to understand what's the purpose of the two diodes connected to the compensation pin (8), and what the output of the comparator is supposed to be. Also, I'd like to remove the 5V supply and ...
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3answers
387 views

Comparator Design

I have designed an inverting comparator circuit with external hysteresis. These are my calculations: Finally the output waveform: The threshold of comparison is high and it's missing most of the ...
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1answer
127 views

obsolete DTL chip substitution

I'm trying to substitute the obsolete NAND chip in this circuit (part of an audio synthesizer) with a standard CMOS one (for example CD4011). The original NAND chip is a DTL chip by Motorola, MC846. ...
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0answers
71 views

What comparator is compatible with OPA2132?

I've designed a circuit but realized now - when the 200+ boards finally arrived - that I've made a mistake. Long story short: I made the prototype on a breadboard, using OPA2132 (because that's what ...
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2answers
730 views

LM339N comparator won't work [duplicate]

I'm making a circuit which basically should turn on a led when it's dark and turn it off when there is more light. To test the light I've used a photoresistor, and to turn the led on/off a comparator (...
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1answer
1k views

Opamp as latching comparator

So I have one unused OpAmp left in my circuit and I would like to use it as "latching comparator" (for lack of a better name), but I'm having hard time wrapping my head around it. Here is how I want ...
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0answers
478 views

Teensy 3.2 Comparator

I am trying to create a comparator on the Teensy 3.2 to convert an IR receiving diode signal from analog to digital. Currently I am using an op amp, but that takes extra space and extra power, both of ...
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2answers
153 views

Inverting input causing current draw on non-inverting input?

Problem: unexplained current draw on non-inverting input when voltage on non-inverting input is above the inverting input. Background: I have been playing around with an RC timing circuit from pg. 24 ...
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2answers
132 views

Multiple voltage sources

Good day, A simple question to improve my understanding of multiple voltage sources. If I have two potentiometers with the wipers connected both to one input on a lm339 comparator, each voltage ...
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5answers
431 views

How to equalise highly asymmetrical rise and fall times?

This question is kinda similar to highly-asymmetrical-rise-and-fall-times, but I think that the data sheet is already suggesting that I'm at the optimum design. Resistor changes were the answer to ...
2
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1answer
654 views

Voltage Comparator IC's Output (LM339) Never Goes To VCC (But Can Go To Ground)

I'm trying to set up the most basic form of voltage comparator using LM339 (http://rohmfs.rohm.com/en/products/databook/datasheet/ic/amp_linear/comparator/ba10393f-e.pdf). I'm giving it 12V supply (...
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2answers
130 views

Proximity Sensor Switch Circuit

My goal is to build a proximity sensor switch circuit that can turn an LED on OR off. If I wave my hand, the light will turn on. Similarly, the light will turn off if I wave my hand the second time. I ...
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1answer
501 views

Input Bias Compensation for a Comparator

I've been working on designing a discrete dual-slope ADC for school, and I've run into a problem. The schematic below shows my proposed input stage, an ideal integrator connected to a comparator. I've ...
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1answer
141 views

LM239 Supply/Open Collector Output Voltage

I wish to power LM239 comparator from a +5V single supply and use the open-collector output to switch a 24V load (resistor plus LED). Is this permissible? http://www.ti.com/lit/ds/symlink/lm239a.pdf