Questions tagged [current-sensing]

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1answer
66 views

How do you analyze this simple circuit? [closed]

I want to plot Vout vs time graph (which software do you suggest) and also want to find out max and min output voltage (Vout) of the circuit. How can I find the max and min manually? Can I find them ...
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2answers
54 views

non-inverting current sense op amp output unstable during the measurement

I would like some advice on how to solve the following problem. The following circuit is motor driver with current sense circuit. The circuit run motor at cca 30mV when is not under load, but when the ...
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0answers
20 views

Multiple statuses displayed in LEDs and piezo [sometimes]

Essentially [and this may sound a little overkill] I'd like to run current sensors from three sources to indicate whether electric or EM locks are engaged and to feed off of reed sensors to feed the ...
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2answers
53 views

Current sensing relay that momentarily closes contact each time state changes

I have a 240V dust collector that I manually switch on and off using a one-button wireless remote. The dust collector is connected to several machines. I'd like to use a current sensing relay to ...
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2answers
179 views

How to measure very low current by amplifying it?

I am trying to measure current from a DC circuit. So it basically I am trying to make an ammeter. I am using ACS712 20A current sensor and Arduino UNO. Theoretically, I can measure a minimum of 50 mA ...
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1answer
554 views

Can a floating capacitor terminal be used to collect electrons?

I want to collect charge from an electron beam source. For that, I'm proposing to put a floating capacitor with its bottom terminal floating and directly exposed to the electron beam gun. The top ...
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0answers
25 views

Sensing Ground Faults on a High Voltage Pulser - Coupled Inductor Issue in LTSpice

I am building a ground-fault protected High Voltage Pulser. The pulses may be as high as 500V and as narrow as 50us (20kHz). The question of how to create GFCI protection is proving to be a ...
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0answers
40 views

CMRR error calculation

I need to calculate CMRR error for the current sense circuit. From Texas Instruments I have the following formula to calculate the CMRR error: Schematic of my device looks like this: There are two ...
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1answer
17 views

Switched Mono jack + battery: Make circuit when plugged in

I would like to replicate the functionality inside the Ampoids guitar amp (9v battery) in which the circuit is turned on only when you plugin a male 6.3mm mono jack to it I believe that the most ...
1
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1answer
30 views

Dedicated current sense amplifier vs simp,e difference amplifier

I need to implement low-side current sensing for a H-bridge motor driver. While there are dedicated current sense amplifiers such as TI’s INA180, can I use a simple difference amplifier for this with ...
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2answers
56 views

Why most non-invasive current sensors have a minijack at the other end?

If I search on google for non-invasive current sensor and click on the images tab, in most cases, I see a minijack at the other side of the wire. What is the reason for this? Is this minijack supposed ...
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1answer
118 views

Compact Voltage-Controlled Current Source Array

I'll start by asking what it seems to me a trivial but I don't know what is the most efficient solution. Electronics is not my main occupation, so I may need some indication to proceed: I need to ...
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1answer
85 views

Adjustable CC/CV supply with voltage and current limiting having no output voltage at low voltage levels?

Im trying to create a power supply with an addjustable output between 0-12V or 0-3A (CV and CC adjustable). To make sure that the components don’t get damaged I'm trying to implement a protection for ...
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1answer
35 views

How to share a current sense pin on a single GPIO

The BTS7040 is a 2 channel High Side Switch with diagnostic feature, im planning on using 2 of the IC and i dont have extra GPIOs to spare. The way you read a fault from the BTS7040 is to select a ...
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1answer
46 views

Detect power outage and disconnect heavy loads from the UPS [closed]

I am looking for a simple system to detect power outage and disconnect heavy loads from the UPS backup to maximize the longevity of the power backup. The UPS works on a 24-V battery. The UPS switch ...
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0answers
24 views

Current sensing, clearance, trace width

I have to design simple PCB that will measure current by shunt resistor(R7, R8, R9) and voltage by divider. Board has 3xin and 3xout for different voltage/current specifications. I have the following ...
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1answer
367 views

INA219 current sensor not working properly with DC motor

I use INA219 module to read DC motor current for control propose. I connect INA219 in series with motor as shown in schematic. simulate this circuit – Schematic created using CircuitLab The ...
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1answer
78 views

Current Sense circuit with digitally programmable gain

I'm designing a precision source meter and I wanted to put a couple ideas out to the community. One thing I will note is that this device has 32 channels, so I need to be very cognizant about both ...
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0answers
79 views

How to average output of current sensor to get smooth output?

I am using INA138 current sensor with 100Hz, PWM duty 5%, 8-bit resolution signal load is a resistor, I getting zero readings while actual current readings also appear, edited - zero current sense ...
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0answers
28 views

Designing high bandwidth current sensors for inductor current sensing

I am designing a high-frequency current sensor, suitable for sensing +/- 20 Amps at frequencies of 200kHz. This is being used in average current mode control application in an isolated forward ...
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1answer
85 views

Low Side Current Sensing Grounding Question

I recently made a low side current sense circuit to test a power supply. It works well, but I am trying to understand the strange behavior that happens when I apply the negative lead of my probe to ...
0
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1answer
190 views

Microamp-milliamp Measuring Circuit: will my circuit work? Feedback/Advice

I'm developing a device which must be able to measure milliamps and microamps on one of its lines (down to 1 microamp, but also clearly seeing if it's less than 1uA). It's going to be DC of different ...
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2answers
162 views

Converting a 4-20mA 24V signal to 0-5V?

How do I convert a 4-20mA 24V signal to a 0-5V signal, suitable for A-D conversion with a 5V microprocessor? Can this be done while isolating the 24V from the 5V output?
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0answers
42 views

Detect Battery Insertion in USB Charging Circuit

I'm using an MCP73831T as the charger IC, I've figured out how to detect the charging/charged, this was easy, however, I would like to know when the battery is actually plugged in, I know when the usb ...
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1answer
176 views

Current sense op-amp with integrated shunt vs expensive resistor

To simplify my question lets assume: I need to convert +/-7.07A RMS AC current into +/-707mV RMS voltage with high acurracy (0.1% or better). It may be also higher voltage, up to +/-2.5Vpk. For now ...
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1answer
36 views

How to sense current AC of a sinusoide -100mA to 100mA with 70kHz

Any suggestions about a chip or PCB component that could work? I tried to use the the current sense transformer PA1005.050NLT https://www.digikey.com/product-detail/en/pulse-electronics-power/PA1005....
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1answer
98 views

Current Sense Amplifier Potentials

I'm trying to implement a current sense amplifier in my application, but I have a question about setting it up with regards to current flow. Basically, in this case, you put a very small shunt ...
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3answers
323 views

Current Sensing on positive and negative voltage rails

I'm working on a design that uses two separate buck regulators to generate a positive and negative voltage, and I'm trying to implement current limiting with a current sensor. However, I am running ...
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2answers
83 views

I am looking for a 40 input OR gate which minimize PCB space

I am using 40x ICs INA301 to measure overcurrent in 40 interfaces Finally I want to have 1 single "output" to signal if there is an overcurrent in ANY of the 40 interfaces I don't want to utilize any ...
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4answers
99 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
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1answer
134 views

Reading registers from ACS71020 over SPI

I'm trying to read registers from current-sensing chip ACS71020 connected over SPI. This is how I initialize the SPI: ...
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2answers
70 views

AC phase current sensing using Isolated delta-sigma modulator

I am trying to design a isolated AC current sensor. I've chosen the AMC1106 Isolated Delta-Sigma Modulator. (change my mind if you think there is a better solution for 220V AC; 2A Max; 0.25%) The ...
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0answers
23 views

Dual channel current sense circuit design

First of all if this isn't the correct place for a post such as this please tell me where I should post it. I need a circuit that will allow me to measure the current of two solenoid operated pump ...
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1answer
58 views

Load sensing relay/power switch/adapter which switches on when it detects some load on its input

Complete newbie here. I'm not using the right terms, so my apologies in advance. The problem is simple. I want my powered computer speakers (2.1) to turn off when the computer is turned off. I have ...
0
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1answer
42 views

Method for sensing fault currents with microcontroller

How do I choose a proper approach for detecting ground fault currents (20 mA through 30A, 60Hz)? Let's say I have a zero sequence CT and calculate a burden resistor. I have a 12-bit ADC in the micro. ...
2
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1answer
74 views

Measuring AC Current at High Voltages (up to 600VAC)

I've been looking at various ways to measure current for a while now, and am stumped on how to read high-side AC Current Measurements ohmically (no Hall Effect sensors). My initial thought was to use ...
0
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1answer
114 views

op-amp level shifter

I'm working on a brushed dc motor driver and I have to monitor the current. so I use ACHS-7121 current sensor. This sensor convert +-10A into 0V to +5V and have +2.5V in zero current. Now I want to ...
1
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1answer
239 views

Current Sensing with Op-Amp, do I need a shunt resistor in series with the load on the output?

Hi I am building a circuit to measure current draw from a load, I opted for a voltage follower with a transistor and a shunt in between, The transistor is needed to allow higher currents to flow ...
0
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1answer
316 views

Current sensing relay with delay on break for dust collection system

I am in the process of planning our a new workshop in a single car garage. I have a large 20A Dust Collector that needs to be on its own circuit or else it will trip. I also have a ceiling mounted ...
2
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3answers
589 views

Detecting switch closure

Any techniques/circuits/sensors that can determine the open/closed state of a set of contacts, independently of whatever power or signals are being switched by the contacts? Obviously easy if there's ...
0
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1answer
58 views

Output current and voltage levels regulation in ac/dc adapter

On the picture below is the output circuit of AC/DC adapter. I understand how voltage level contol works, but I don't understand how exactly current limitation works and how should I calculate ...
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1answer
346 views

High voltage and cheap differential amplifier

Can I use a LM324N (very common) op-amp to act as a high-side differential current sense op amp at high voltage? The Differential Amplifier The differential input voltage rating is 32v, but my load ...
0
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1answer
30 views

Current monitor output doesn't respond to load changes

When I physically build this circuit the output voltage doesn't response to load variation. The voltage across the sense resistor is definitely increasing when decrease the load resistance, the ...
0
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1answer
70 views

Measuring high currents with toroids

I got a PT27312 current sensor (datasheet), I wonder if I can use it to measure currents up to 100A AC/DC. I couldn't find any specifications in respect of the current measurement range. I only know ...
0
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1answer
108 views

Working Voltage for Basic/Reinforced Isolation (ACS712)

I'm planing to use current sense chip ACS712. I don't understand some values in its datasheet, page 2 (Isolation Characteristics). I understand "Dielectric Strength Test Voltage - 2100VAC" - that ...
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2answers
172 views

“ground disturbance” in current sensing with shunt resistor

There are lots of questions about "traditional" low-side current sensing using a shunt resistor. Most discussions and papers mention the drawback of "ground disturbance" introduced by the measurement ...
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1answer
40 views

XADC Current Sensing Reference Design

Please refer to this reference design for AC701 (snippet below). The schematics, specifically the current sensing sections in pages 34-36, show this: I want to understand why, for the REF output of ...
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2answers
483 views

How to connect multiple sensors to single PLC input?

Hello. I have a scenario where I have multiple PNP "error signal" from several sensors (let's assume 3 for now). If the sensor output is HIGH, then there is error. If the sensor output is LOW, then ...
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8answers
13k views

What is negative current?

I understand that voltage is relative to ground, so that can be negative. However, I'm currently looking at current-sensors (ACS712 current sensor) and in the performance characteristics table, it ...
0
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1answer
60 views

Current transducer - understanding of turns ratio connection

I'm using a LEM LAH 25-NP current sensor and I don't understand the recommended PCB connections in the table from the datasheet. I understand the first one, but what is with the second and third? What ...