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

learn more… | top users | synonyms

-1
votes
1answer
60 views

My Tiny Comparator

I just can't seem to get this to work. simulate this circuit – Schematic created using CircuitLab The diodes were supposed to prevent this from going in "reverse-mode", should the ...
1
vote
2answers
50 views

Problem with using comparator to amplify signal

I want to use LM293(comparator) to amplify signal. The input signal from 0 to 2.5V, and make the output signal double(from 0 to 5V). Then I use the LM293, and I do the simulation first, it works ...
1
vote
1answer
45 views

H-Bridge controlling circuit

I'm in need of an H-Bridge capable of driving moderate-high current for motors on a small car (7A peak, 2-3A nominal, 12-14 VDC), and I'm hoping to control it with two (2) digital pins (5 VDC). I've ...
1
vote
1answer
43 views

Best way to compare value in register with constant assembly AVR

I am newbie in assembly and AVR, I wonder what is the best way to compare two values like in C ...
0
votes
2answers
48 views

Recommended approach to create a lead acid battery level circuit

I want to build a battery level indicator circuit for a 12 V sealed lead acid battery. The battery indicator circuit will have two functions: It will power 4 LEDs to show the level of the battery ...
2
votes
4answers
293 views

Question about 1-bit Analog-to-Digital Converter

I am working on a research project, and for a part of it I have to turn an analog signal into a digital one. Now, electronics is not my forte so I don't know what I am doing and am feeling around in ...
0
votes
3answers
74 views

Fast 220v AC power failure detection

I'm building an AC-Detection circuit. I want to detect when the AC power has failed ASAP so that I can react very quickly. (like 1-3ms should be enough time) This was my first idea. It works in ...
0
votes
1answer
48 views

Implementation of 4-bit subtractor

How to implement subtractor of two 4-bit numbers using subtractors of two 1-bit numbers as a module(no assembler coding, just expressions in boolean algebra)? If there are four 1-bit subtractors, how ...
-1
votes
2answers
74 views

How exactly does a comparator work?

How exactly does a comparator work? Comparators have many uses and its concept is not too hard to grasp. What I don't understand however is how exactly it compares two voltages. How does it know ...
2
votes
1answer
146 views

Can someone explain how this transistor comparator works?

I am looking to make a comparator using transistors and I stumble across this circuit claiming to be one: Unfortunately, the description that came along with it leaves a lot to be desired, ...
0
votes
2answers
63 views

Timing circuit with op amps and capacitors

I understand how a basic comparator op amp works and how a capacitor charges individually, but I can't seem to put it all together to make this circuit. I think I might be messing up with the voltage ...
0
votes
1answer
29 views

Comparator model suggestion for overvoltage protection circuit

It's a pretty simple circuit. I'm measuring a voltage with an ADC, which has a max input of 5V. The signal I'm measuring goes to the drain of a F12N10L MOSFET. The MOSFET's source is connected to ...
0
votes
2answers
138 views

LM321 Comparator - Short circuit indicator. Possible to design a bi-color LED version?

Recently, I began work on a adjustable regulated power circuit in search of a short circuit protection / indicator add on. A fellow forum user issued a solution that involved an LM321 as a comparator ...
0
votes
0answers
11 views

How does this regenerative latch push the circuit into saturation or 0 V

I am looking into this circuit which is a comparator latch. In the above diagram there are 2 gain stages. For the first 1 , a PMOS is used as a load and an NMOS for the second stage. If the ...
-1
votes
1answer
32 views

What is E/A mean?

I'm trying to understand how is UCC28703 PWM-controller work. But I don't understand what do the following pictures mean: and . I know they are comparators, but i don't know what is E/A mean and ...
0
votes
5answers
88 views

Reducing the voltage drop on a simple comparator driving a MOSFET to avoid LiIon overdischarge

I would like to use a LiIon cell recovered from an old laptop to power my bike light (a bulb one, 2.4W 6V). I thought about using an opamp controlling a MOSFET to avoid overdischarge (MOSFET ON for ...
0
votes
2answers
41 views

Where am I going wrong with the comparator in MSP430?

I am getting up-to-speed on the TI MSP430. I am attempting to write code in C to access the built-in comparator on MSP430G2553. I've got a simple program for the comparator but I must be doing ...
1
vote
0answers
35 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? ...
2
votes
2answers
70 views

Muxes, Adders, Comparators, and Gates

This question is actually from one of my previous discussions, which I still don't understand how to implement. The goal is to use abstraction to design a circuit, which converts two-digit ASCII ...
1
vote
0answers
63 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 ...
-1
votes
1answer
70 views

comparator problem

where is the mistake in my circuit? i attempted to create simple continuity tester, image really explains it pretty much. IC - ne5532p PS: i know reference voltages on two op amp (+) terminals are ...
0
votes
0answers
38 views

How can I build a comparator for AC?

This simple scheme to compare Vin1 and Vin2 does work for DC current, but how do I build a comparator for AC current? In fact I would like to compare the RMS values. The purpose of the comparator ...
0
votes
1answer
128 views

How could I go about building a 2-bit comparator that compares two 2-bit numbers and determines whether one is greater than or equal to the other?

Using an 8:1 multiplexer, I understand there are three inputs, so I'm not sure how I'd go about getting two 2-bit numbers, which would be four variables, not three. Any pointers on how to get started ...
0
votes
2answers
106 views

Understanding decoders and comparators

How can I implement the comparator of two 2-bit numbers using decoders DEC 2/4 and required logic gates? That comparator will be used to compare two 4-bit numbers. The comparator only has one output ...
1
vote
1answer
186 views

dsPIC33E comparator interrupt doesn't occur

I'm currently trying to get the comparator on dsPIC33EP256GP502 works, but get stuck in the comparator interrupt. Basically what i want to do is just using the comparator to compare two external ...
2
votes
2answers
97 views

How to derive the node voltage for this comparator with hysteresis?

I have the following circuit. U26 is a simple unity buffer and U15 is just a dual comparator. I want the top comparator to compare the battery voltage (VBAT/2) on the inverting input with 2.0V ...
1
vote
1answer
77 views

Comparators as op-amp integrator

So I figured I need an audio range function generator and was thinking of generating a square wave with a 555 and then using op-amps to integrate it into a triangle and sine. Since I happen to have ...
0
votes
2answers
134 views

Purpose of gate driver in Class D amplifier

Can somebody explain to me why we need MOSFET gate driver in class D amplifier like in the picture below(common class D schematics)? What I don't understand is if we for example have 9V rails, then ...
8
votes
4answers
748 views

Controlling heater with PWM through MOSFET

I'm trying to control a heater coil (resistance ~0.9 Ohm) with PWM using a MOSFET. PWM modulator is based on LM393, MOSFET is IRFR3704 (20V, 60A). If I place 1k resistor in place of heater ...
0
votes
1answer
45 views

How to implement a current controlled voltage source, or a comparator that trips once a certain current is reached?

I have current flowing through a CCVS, once 10A is reached, the CCVS puts out 10V, which takes a comparator's output high. The current that goes through the CCVS continuous to the load. Is there a way ...
0
votes
5answers
201 views

Square wave generator

Can you explain what for is resistance R101 on next schematic: I understand why we need R105 (open collector) and R102 (positive feedback). But R101? and C11? Thank you.
0
votes
1answer
67 views

Downshifting binary signal from higher to lower voltage using an LM339 comparator

I'm working on an experiment where I'd like to shift a 24V on/off signal down to 3.5V or 5V (i.e. suitable to use with an Arduino or Raspberry Pi). For simplicity and safety - I really don't want to ...
0
votes
1answer
154 views

Designing a 2 bit magnitude comparator [duplicate]

As a foreword I would like to say that I am asking this question as part of a computer science course assignment, and any responses here might be referenced in my report. I am ideally looking for ...
1
vote
3answers
204 views

What is the drawback of a high-value resistor for positive comparator feedback / hysteresis?

I'm building a simple circuit which has an LM211 comparator at its heart. The positive input is connected to a 10k-10k resistor divider across the supplies, stabilized by a 1uF capacitor. Hysteresis ...
0
votes
1answer
85 views

Ambient Light Sensor + Comparator

So I've been looking at options to create a way of controlling whether a flash will fire based on the amount of light in the surrounding environment. Early note: Everything has to be surface mount ...
1
vote
1answer
46 views

Comparator input interfacing

I need to digitize a weak (-10 dBm) 1-20 MHz signal with a comparator. The output of the preceding stage is 50 ohm. The comparator I'm using is the LT1715. It's input trip point is ± 5 mV and the ...
1
vote
1answer
126 views

OP amp voltage comparator for an FET

I have a project requiring a switch (I supply 4.8V, the switch stays off. I supply 5V, it turns on.) After some testing and asking several questions, I realized that the MOSFET I was using would not ...
0
votes
2answers
128 views

Opamp comparator output interfacing with digital circuit

I want to use Op amp as a comparator to shape the 50Hz sine wave to square wave, then route it to the PLL reference signal input, the PLL chip is 74HC4046. And i use AC coupled method. Because the ...
3
votes
1answer
786 views

Negative feedback capacitor in Op-Amp comparator circuit

This is a part of a circuit of a big device. I'm interesting why need for C1 capacitor? OA2 is a general purpose opamp. Power supply for the opamp is +15V/-15V, sorry for mistakes in the picture. ...
0
votes
1answer
76 views

Using an H-Bridge like a comparator

I'm wondering if there's a way to use an H-bridge like a comparator- That is, if one input is greater voltage than the other, then the attached motor spins one way, and vice versa, and it doesn't spin ...
0
votes
1answer
89 views

LM2903 Comparator output oscillates

I am using an LM2903 Comparator on my design to measure sensor signal. Constant current source is provided to the sensor by means of resistors (connected to 2.5V). I have an RC input filter ...
2
votes
2answers
92 views

Protecting a comparator in a tension measurement device

I am building a device to measure the tension of a conducting wire using an Arduino. The basic circuit concept consists of two stages: The wire is placed in a strong magnetic field. Then the ...
0
votes
1answer
182 views

LC comparator based oscillator

I am trying to build a LC oscillator based on LM393 open-collector comparator, but am having some difficulties. This is the current circuit: I was expecting to get a nice square wave with one ...
0
votes
1answer
160 views

Voltage Comparator Circuit Output 0V or 5V

I'd like to build a very simple voltage comparator circuit with the following properties: Vs = 5V V- = Ground Vout = 5V if V+ >= 200mV Vout = 0V if V+ < 200mV I'm using this comparator: ...
0
votes
2answers
313 views

Thermocouple Simulation Test Circuit and Voltage Comparator Circuit

I have a challenge that I would like to share with you. (at least a challenge for me) The resistor R8 (10 turn potentiometer) can be adjusted from ~0 to 1K Ohm to output voltages from 3mv to 30mv. ...
0
votes
2answers
70 views

Comparator Output Swing Measurement

i wan't to measure the maximum and minimum output swing of a Comparator. I'm using the circuit which you can find attached. However, since the Output of the Comparator (TI LM2903) is open drain, I ...
2
votes
1answer
391 views

What's the purpose of the 1M resistor in this comparator circuit?

I find this circuit from ON Semiconductor's LM211 datasheet. There is a 1M resistor from negative power rail to the 'reference' input. ON doesn't describe the circuit's function. I think it's a ...
1
vote
3answers
194 views

What type of Op Amp or comparator has a schematic symbol with hysteresis like symbol

I already know it is not a schmitt trigger, it looks like it is used as an open loop amplifier taking a reference voltage on the (+) and the V0 is fed into a schmitt trigger. I have no other data. ...
1
vote
2answers
84 views

The direction of the bias current of LM311

I thought the conventional method to denote the direction of the bias current is to precede the IIB parameters with the '+' or '-' flag in the 'electrical characteristic' table, '+' indicate the bias ...
2
votes
4answers
497 views

Why do they usually make comparators open collector?

I never see open collector opamps while I frequently see open collector comparators. What is reason for preferring open collector output in comparators? (Inside of LM193.)