Questions tagged [comparator]

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

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1answer
189 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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3answers
174 views

Considerations when using Opamp as comparator

For cost reasons, I want to use an opamp as a comparator. So far in terms of making sure the opamp is suitable, I have: Making sure the output can slew fast enough Making sure it can handle large ...
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0answers
193 views

Digital Comparator from LSB to MSB using Lookahead

This is homework to be upfront, but I'm really stuck on it and just need some kind of direction. I've been assigned to create a 16-bit lookahead comparator going from LSB to MSB using no more than 4-...
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0answers
176 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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0answers
82 views

LPV7215 comparator misbehaving in simulation

I'm simulating the following comparator circuit using TINA-TI (Version 9.3.150.4 SF-TI). The behavior, however, is not as expected: Hopefully it is clear that V- remains constant, while V+ swings ...
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0answers
300 views

How do I do signal comparison without using opamp?

I want to remove the opamp IC seen in the schematic below with the least number of transistors possible in order to simplify the circuit, reduce cost and increase switching performance when used with ...
2
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0answers
184 views

comparator input latches high?

I am using a a TI TLV3202 comparator (U2B) with a bridge circuit as shown in the schematic below. It is followed by a DG4157 analog switch. This is related to this question I had asked earlier. ...
2
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1answer
356 views

How to calculate hysteresis when the OPAMP supply voltage is changing

I have designed a GSM/GPS based tracker which is installed at my bike. But it is draining battery too quickly. So, I want to add a cutoff circuit when the bike is not running(battery not charging) ...
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4answers
452 views

Comparator output not fully switching on MOSFET

First Question for me. I have benefited from other answers here but have not fully resolved my problem. Here's my problem... The LM311 Comparator output does not drive the N channel MOSFET fully on....
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0answers
129 views

Comparing sine wave and triangular for spwm using comparator

i am trying to generate sinusoidal PWM by comparing sine and triangular wave. First i just tried to compare sine wave with reference voltage in order to check the working of op-amp. I get a problem ...
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2answers
96 views

Design Considerations for comparator with ~1mV accuracy?

I am working on building an "exploded" analog to digital converter (ADC) (tracking type: up-down counting) for teaching purposes. I am working with a 0-5V reference, and 12-bits of precision (values ...
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0answers
43 views

How do I draw the truth table of an adder/subtractor that sets flags, and those flags are the inputs of a comparator?

How do I draw a truth table of a circuit that : starts off with a full adder/subtractor outputs the result F based on the two inputs (add if opcode is 0, subtract if opcode is 1) then output three ...
1
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1answer
119 views

MCP6548 comparator circuit isn't working

Hey guys back at it again, sorry. I am using a standard MCP6548 Comparator to finish the first stage of my project. simulate this circuit – Schematic created using CircuitLab OP's schematic....
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0answers
70 views

IC for magnetic environments

I am working on a comparator circuit for converting a small AC signal to a digital (square) signal. The circuit is meant to be used in a strong magnetic environment, so the casing should not have ...
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0answers
120 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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1answer
149 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
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1answer
562 views

Preamplifier before latch stage in comparator circuit

Adding preamplifier based on simple inverter before latch stage can improve performance of comparator by decreasing offset voltage. Can anybody explain me how it works? Best Regards
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0answers
95 views

Port A digital output set up on pic16lf1827

I am having difficulty moving my code from port b to port a on pic. I am looking at adc disabling and also comparator disabling, but not having much joy. Anyone see what I'm doing wrong? ...
1
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1answer
183 views

BJT schmitt trigger has linear behavior on negative swings

I am currently building a VCO for an analog synthesizer. The circuit produces a triangle wave by taking a Schmitt trigger output and feeding it into an integrator. The constant output of the Schmitt ...
0
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1answer
28 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). ...
0
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2answers
62 views

Dual slope edge detection for a phototransistor

I want to detect sudden changes in light level using a phototransistor. The goal is to transmit information optically using the timing of the transitions, ideally using an LCD screen. LCD transitions ...
0
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1answer
53 views

output of comparator

I am using LM139 comparator There are two stages of the circuit: First stage is amplifier stage Second is comparator stage I apply input signal of 1.098Vac to noniniverting input of LM139 comparator....
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27 views

two stage open loop comparator question

I am trying to understand the operation of a two stage open loop comparator. simulate this circuit – Schematic created using CircuitLab What is shown is the output stage, current-sink inverter....
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1answer
80 views

Comparator loses voltage when connected to mosfet

I want to make a discharger for 18650 batteries so I can store them at a specific voltage. I built a comparator (LM393) with a voltage reference to 3.8V at the inverting input and the voltage of the ...
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0answers
48 views

Solar power pump - Design critique and help

Okay so, I have a design that 'works' on the breadboard. But I feel like it could use some improvement. Here is my current design: simulate this circuit – Schematic created using CircuitLab ...
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1answer
65 views

Relaxation Oscillator Issue, comparator self-oscillating at 25 MHz (40ns propagation delay)

I have a relaxation oscillator circuit, which is supposed to oscillate around 6 MHz, and mostly it oscillates in a very stable manner around it. However sometimes it starts to oscillate at 25 MHz, ...
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0answers
92 views

wrong frequency of LC based generator with LM311

I have a problem with the frequency of LC meter based on comparator (a very popular solution, similar to this one: http://www.vk6fh.com/vk6fh/lc_meter_vk6fh.htm). I have recreated generator part in ...
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0answers
40 views

how to power up a subtractor using a window comparator?

I'm making a circuit that will detect whether a voltage(V1)is in between the range 1-2 V. If so I want to switch ON a subtractor and output V1 - 1 V. I initially thought of connecting the output of ...
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0answers
38 views

Comparator resolving input voltages close to vdd

I have a design problem to solve. The problem statement goes as follows: "Design a clocked comparator resolving input voltages close to vdd dissipating less than 100 uA". What does "resolving input ...
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1answer
49 views

Basic circuit to turn on LED when input detects signal (for guitar)

I'm looking for a basic circuit snipping which can either turn on an LED or give a positive voltage when input signal from a guitar is detected. Basically, I have an existing circuit where an effect (...
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1answer
68 views

How to interface a passive inductance sensor output (audio-level signal) with Arduino?

Would like to interface two passive magnetic-inductance sensors output (audio-level signal) with Arduino. The sensor circuit comprises of two wire-wound sensors and has no power. It generates it's ...
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0answers
149 views

Why does my LM393N (dual comparator) ignore its inputs completely when used with an LED?

I have made the following circuit: Viusalisation (not working): https://i.stack.imgur.com/tDA85.png Circuit (working): simulate this circuit – Schematic created using CircuitLab Left to ...
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1answer
38 views

Voltage alarm with LT1017

With help of this site, I have redeveloped my voltage alarm circuit (see my previous question for the history). I started off with an 741 Opamp and it did not work as I wanted it to work (Thanks for ...
0
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1answer
110 views

How do I make a discrete voltage detector?

I would like to design a circuit which has outputs LOW when the voltage it is connected to is below a threshold, like 3.3V. There are some ic's you can buy to do this, but I would like to make my ...
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47 views

Voltage Divider for Comparator Threshold

I am trying to understand how the voltage on the negative pin of U2A of the below circuit is 1V/2.4V. From the author: "Threshold signal is 0V/5V but it changes ...
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2answers
102 views

OpAmp Comparator Circuit Design for High/Low voltage measurement

I am new to this. I want to make a circuit to measure the voltage from (0 ~12 V), which can have 2 op-amps as comparator to give the output positive, when the voltage goes from 8 V to 12 V and give ...
0
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1answer
465 views

How to compare an AC signal with a DC reference using a comparator?

To answer the title question, the only way I could think of is this but they don't seem to be working. The AC RMS voltage at the input is 33 V and the reference voltage at pin 3 is 2.6 V. Voltage at ...
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2answers
299 views

How to deal with strobe and balance pins of this comparator for single supply operation?

I want to use this LM311 comparator with a single supply. But these are pins called balance and strobe which confuses me. What are these for? In a forum I read someone suggests pin 5 and pin 6 ...
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2answers
288 views

Questions regarding a comparator circuit coupling to an analog switch

This is directly related to my previous question, so it requires to first have a look at that. And the below LTspice implementation is based on Andy Aka's answer. The following circuit works in ...
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0answers
58 views

Peak detection comparator simulation problem.(Process and no VSS version)

Here is a peak detection comparator schematic and simulation,i have three question about them. 1.Why is there a high signal in C point,but not in A and B point? 2.There is VSS in this peak detection ...
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1answer
92 views

Voltage Detection via Analog Comparator

I'm currently designing a PCB at which I have an lithium ion battery (4.3V max) attached. The battery is charged via USB (5V). The charging controller is enabled by a microcontroller which should ...
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0answers
122 views

Strange output from latch connected to comparator

I'm trying to make a latch (in ltspice), so if the comparator output (A) goes low, the latch will trigger and C will go high. C should stay high, irrespective of whether A goes high or low after that. ...
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0answers
63 views

The reason why will the VDC influence the output of comparator

There is my schematic,teacher gave us,for the comparator, Theoretically,when the black line is bigger than blue,the red one will become "signal one".but i found the vdc value will influence the output ...
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1answer
397 views

Comparing and adding numbers using multiplexers and comparators

Supposing I have been given three two bit numbers, a1a0,b1b0,c1c0 then what is the best way to design a circuit that gets the largest two of the three and adds them?
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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 ...
0
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1answer
244 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
46 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 ...
0
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1answer
130 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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0answers
73 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
145 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. ...