Questions tagged [comparator]

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

Filter by
Sorted by
Tagged with
2
votes
1answer
162 views

Transistor differential comparator threshold

It seems that the circuit bellow acts as a differential comparator. I confirmed it by simulation on LTSpice. simulate this circuit – Schematic created using CircuitLab I remark that output ...
0
votes
1answer
123 views

Why does my comparator not compare?

I have designed a buck converter and I am baffled with its comparator's functionality. The op-amp comparator does not give a PWM, instead it gives an amplified ramp. What am I doing wrong?
1
vote
1answer
30 views

How to determine the value for the gate resistor (Rg) of a MOSFET in low side configuration?

Once the FSR is pressed the output of the comparator should go high. This, will drive the MOSFET ON which has a DC motor on its drain terminal. I was wondering how can I determine the value in ohms of ...
0
votes
1answer
31 views

Should I include a pull-up resistor for this application? simple schematic

Once the FSR is pressed the output of the comparator should go high. Since there is not really any "delicate" logic behind this schematic I was wondering if a pull-up resistor is really necessary for ...
0
votes
2answers
24 views

three points (two slopes) op amp conditioning circuit

I'd like to get the output on the right when applying the signal on the left to a signal conditioning circuit using op amps. I've got different slopes so I guess I need two amplifier circuits with ...
0
votes
1answer
46 views

Zero crossing detector using 311 comparator

Is the explanation correct? The output on positive voltage should be high and on negative voltage it should be low.
0
votes
1answer
16 views

Which comparator type to use as an On/Off switch for a DC motor via FSR (force sensing resistor)

I want to use an FSR (force sensing resistor) to turn on a 300-350mA (steady state) 4 volt DC motor while one press into the FSR. As the image shows my plan is to have a voltage divider between the ...
1
vote
2answers
47 views

Best practice when choosing a trim pot value

I have a basic comparator circuit I'm working on designing. I want one of the reference voltages to be tunable, so using a trim pot. My Vcc is 12V, so assuming a 1/4 watt pot, 1k seems like the lowest ...
1
vote
1answer
39 views

Is there a way to compare both signed and unsigned binary words?

By that I mean, is there a circuit that can compare two signed words against one another, but also be able to compare two unsiged words together, not comparing a signed word to an unsigned one. I am ...
0
votes
0answers
28 views

Low power consumption problem

I have a pressure sensor which is working in the feet of a person which senses the pressure. I'm using nRF processor for sending just ON/OFF signal to the motors. The problem is I'm using a battery ...
4
votes
4answers
81 views

Charge indicator with comparator - very sensitive to noise

I need an indicator when the current from my charger is larger than 100mA. I tried the below circuit but this seems very sensitivity to noise. Probably I am getting some ripple in the mV range from ...
-1
votes
1answer
42 views

how the comparator amp works as integrated amplifier [closed]

I need some explain how does comparator work as zero cross detection and integrated amp
0
votes
2answers
85 views

Schmitt Trigger design

Vcc=5V, Vin= a noisy input voltag I'm designing a non-inverting schmitt trigger using voltage divider. As shown from the image, I designed it on LTSpice and I got the desired results but from the ...
1
vote
1answer
71 views

High voltage comparator [closed]

We are trying to make an high voltage window comparator circuit The following are the design constraints I cannot resistor divide the voltage as it would load the input Unable to find a high voltage ...
2
votes
2answers
68 views

LM311 output stays at Vee regardless of input voltage

I have wired up the LM311 circuit shown in the figure below. It should work as follows (at least to my understanding), when V+ (pin 2) > V- (pin 3) the output (pin 7) should rise to 12V and when V+ &...
0
votes
1answer
83 views

Dual OP AMP setup circuit supposed to pull 2mA, but where is the other 4mA going?

This circuit uses half of the TI dual OPA2626 (not showing the other half of the OP AMP). This dual OP AMP supposed to use 2mA, but it's pulling around 6.8mA (measured at the Grnd pin and also at the ...
1
vote
1answer
84 views

Open collector / drain question

I'm trying to to find the best way to force an inverting amplifier to postive saturation with a gate input, but otherwise leave the function of the op-amp intact. I've come up with a few ways to do ...
3
votes
0answers
32 views

Current mirror configuration analysis in LM393

I've been trying to figure out how this comparator (LM393) works. So far I can recognize the sections: Q8, Q9, Q10, Q12 form the differential amplifier. Q15 and Q16 are the output transistors. Q1, ...
1
vote
1answer
34 views

Reference voltage for a comparator

The question is to determine the reference voltage for the comparator shown in the figure below: After I understood that by the reference voltage is meant the voltage at the negative terminal, then I ...
1
vote
1answer
72 views

How to stabilize a Comparator op amp from static currents?

With huge gaps in my knowledge I will try my best to explain: This circuit uses two inductive loads L1 and L2 (10 Ohm/0.08mH and 11 Ohm/0.02mH) with ground at each end, and with a common signal going ...
1
vote
0answers
63 views

Testing a LM111P comparator

I have the LM111P voltage comparator (datasheet.) I am learning my ropes with electronics, so I am moving thru the easiest topics to more complicated ones. If I understand correctly, when I provide ...
0
votes
1answer
37 views

Why doesn’t the comparator output go near the power supply voltage?

I had this circuit And the output voltage wasn’t the same as the supply voltage. I wondered that the reason was because the datasheet of the 741C says that the output shouldn’t be larger than the ...
0
votes
1answer
28 views

Does a TLV1391 Need a Pull-up Resistor

Does a TLV1391 Need a Pull-up Resistor on its output to Provide a logic level output? Datasheet: http://www.ti.com/lit/ds/symlink/tlv1391.pdf Is it Open-drain Or Push-Pull? Or is this just the ...
2
votes
0answers
88 views

What's wrong with my comparator

I'm trying to set up a comparator that goes high when the input is above 0V and goes low when the input is below -5V. I've used the datasheet equations to calculate the resistors for a non-inverting ...
0
votes
1answer
58 views

LM393 output flickering?

simulate this circuit – Schematic created using CircuitLab I'm using this circuit to detect if a car engine is running. I tested it and it is working however there is some kind of a problem ...
0
votes
0answers
52 views

How does a voltmeter measure the voltage of a PWM signal?

I have a DC / DC converter in the + -12V output connected to the comparator's power pins. A square wave of 1 kHz is applied to one of the inputs of the comparator. The output of the comparator should ...
0
votes
2answers
63 views

Noisy output from opamp comparator

I built the following circuit to filter noisy pulses from a inductive tachometer pickup. The first opamp (U4D) acts as a peak detector. The second opamp (U4C) is a comparator which uses the output ...
0
votes
1answer
20 views

Why is Comparator Output Offset by -5V with a Unipolar Supply?

This circuit works as desired. It switches at 10mV. But the output is offset by -5V. That is, LOW = -5V and HIGH = 0V, which isn't desired. How to make the outputs LOW = 0V and HIGH = 5V? Link to ...
0
votes
0answers
40 views

Analyzing automatic current switch

I'm trying to learn more about automatic current range switch and stumbled across Nordic's nRF6707 power profiler kit that has very interesting topology to choose between three different current ...
0
votes
1answer
34 views

Comparator with Internal Hysteresis

I need clarification regarding comparators with internal Hysteresis. I have a comparator with internal Hysteresis “X” mv and I am using external feedback resistors to create a hysteresis of “Y” mv. ...
1
vote
1answer
43 views

Noninverting and the inverting Comparator

I was studying the Noninverting and the inverting Comparator with Hysteresis from the book "Practical electronics for inventors". NonInverting Inverting I understand that when the comparator has ...
0
votes
1answer
31 views

What is the cause of the error/unexpected outcome in water temperature control heating system circuit?

Here is the circuit with components I built as shown over here. The title of the circuit is water temperature controlled system. The function of this system is to control the heating while sensing the ...
0
votes
1answer
64 views

Duty cycle detection circuit for square wave

I have two signals coming out of one block. One signal is one period delayed than the other one. Is there any method to detect the duty cycle of these pulses?. Edit: Clk is my original signal. Going ...
0
votes
1answer
57 views

Voltage comparator

I have a circuit where I have to read high and low logic level through a micro-controller. Condition: When the input voltage is above 15V, it should be HIGH logic (2V to 5V.) When the input ...
0
votes
1answer
62 views

Input/output characteristics of opamp circuits involving diodes (fast peak detector and sine-to-block wave converter)

I have these relatively simple circuits of which I need to find the transfer functions. Both circuits involve the use of an OpAmp and a diode after the output of the OpAmp. As an input I have a ...
0
votes
1answer
27 views

The maximum voltage that can be applied to the inputs of the comparator TLV1805Q1?

I'm creating a circuit with a comparator TLV1805-Q1. Question: what maximum voltage can I apply to the comparator inputs and what is the maximum voltage difference between inverted and non-inverted ...
1
vote
0answers
57 views

Comparator with hysteresis calculation

I'm trying to calculate the hysteresis of the comparator using currents but something isn't right. I'd like a little help to find the hysteresis thresholds without the simplified equations. simulate ...
0
votes
0answers
39 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 ...
0
votes
0answers
102 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 ...
1
vote
1answer
37 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 ...
2
votes
1answer
100 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 ...
0
votes
3answers
125 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 ...
0
votes
1answer
47 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 ...
2
votes
1answer
125 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 ...
0
votes
1answer
46 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 ...
7
votes
4answers
939 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 (...
0
votes
2answers
166 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-...
1
vote
2answers
79 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 ...
0
votes
3answers
36 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 ...
0
votes
1answer
424 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 ...

1
2 3 4 5
12