Questions tagged [current-sensing]
The current-sensing tag has no usage guidance.
180 questions
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Unexpected behaviour of current sensing circuit with op-amp
I would like to use the schematic below to measure the output current of a buck converter (0-10 A) and convert it to a voltage of 0-3.3 V which is read by a microcontroller. During startup I sometimes ...
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Can a non-invasive AC current sensor measure DC current? [closed]
Can a non-invasive AC current sensor measure DC current? What is the theory behind it?
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143
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Help understanding conflicting results from INA190 current sense amp
Built a board for a drone that has a few things onboard, though the one that is messing me up is the current sense chip, INA190, though it's most likely not the problem.
Picture 1 show the big yellow ...
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2
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314
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Sensing presence of 220 Vac for MCU
I'd like to use an HCPL3700(M) (datasheet) to sense if a 220 Vac mains is present. In my application, the device needs to raise an alarm if the mains voltage is lost. Backup power will be provided by ...
2
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3
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899
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3-phase inverter low side current sense
The setup
I'm currently doing some experimentation with 3-phase inverters for BLDC motors and current sense. I have at hand this board featuring:
IR2103 MOSFET driver. LIN# inputs are connected to ...
1
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1
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201
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How to select current sense resistors for ir2136 ITRIP signal
Looking at the datasheet of the IR2136 it suggests this little resistor network as input for the ITRIP pin.
https://www.infineon.com/dgdl/Infineon-IR213-DS-v01_00-EN.pdf?fileId=...
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151
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Some questions regarding measuring current using ACS712
I'm using an ACS712 0-5A current sensor to measure the input current to a boost converter for the implementation of MPPT algorithm. To do so, I need to connect the ACS712 chip in series with a PV ...
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2
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98
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How critical is the sense resistor?
In the following topology, two 0.68 ohm resistors are paralleled to result in 0.34 ohm for sensing the source current. Can I use three paralleled 1 ohm resistors to result in 0.333 ohm? Does this ...
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237
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Differential current sensor probe- Ground leakage current measurement probe for oscilloscope
I would like to know what you use to measure differential current which is also leakage current sensing.
Background: In industry , the AC or DC current flowing from inverter/ converter needs to have ...
0
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1
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304
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Most accurate way to measure universal (AC) motor current?
I'm designing a control circuit for a universal (AC) motor (single phase, brushed).
I've simulated the control circuit and it works as expected.
Circuit below is controlled by a STM32G4 series ...
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303
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Current sense resistor vs transimpedance amp vs hall effect current sensor for instrumentation?
I'm using a photomultiplier tube; this creates a current output relative to the number of photons incident to it, on the magnitude of microamps. So, I need a precise and accurate way of measuring very ...
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242
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Unexpected output with INA138 current sensor
I have no experience with current sensing ICs and I'm trying to build a current sensor with an INA138 IC that I've imported into LTspice. From the manufacturer's website, I'm expecting my output to ...
- 105
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2
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285
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Designing a high-side current sensor
I'm trying to design a high-side current sensor for limiting the current in a circuit I'm building however I'm very inexperienced with the operation of high-side current sensors.
This is my circuit:
...
- 105
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171
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Sensing current into a battery while charging
I want to sense the current into a 84 V battery while charging and disconnect it when fully charged using a MOSFET. Is it advisable to use lowside current sensing? I used a noninverting opamp ...
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160
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AC current detection with 1-10mA sensitivity
I need to build a current switch that will be connected to an Arduino (or Raspberry Pi) digital input. I need it to set to HIGH (3.3 V) if the current is above some threshold, and LOW otherwise. The ...
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190
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Voltage divider dropping voltage more than expected
I'm trying to connect an ACS712 current sensor to an ESP32 ADC pin. The ESP32 expects 3.3 V, but the ACS712 can reach 4.5 V.
When there's no current going through the ACS712, its signal is 2.5 V, so I ...
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374
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Why do I have a sudden current peak when PWMing a valve?
I am driving a proportional solenoid valve with PWM from an MCU as follows:
The voltage of the MCU is 3.3 V. The gain of the amplifier is set to 20 V/V. Because the valve consumes 170 mA when fully ...
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215
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Current sense pin detect too quickly (Flyback)
Here is my circuit:
simulate this circuit – Schematic created using CircuitLab
There is two problems:
Firstly, the sense circuit don't open the mosfet at 1V, yet the zener at the V+ in the amp ...
- 75
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2
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241
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Current Sense Amplifier / Differential Amplifier Negative Voltage On GND pin OK?
Right now I'm picking a current sense amplifier for my application, and I'm looking for for amplifiers with maximum offset voltage of below 50uV (and offset and bias currents in nA/pA range).
Luckily, ...
- 3,673
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353
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Isolated Current Shunt Amplifier
I have twenty isolated power supplies (around 40 V max) which need to have their current draw sensed and monitored. I'm currently using a TI INA138 current sense amplifier, which sort of works.
...
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MAX9919 Thermal Pad
I am designing the thermal outline plane of this current amplifier ic in a 4 layer board using Eagle Pro. This board will be made using ENIG process.
After spent so much time trying to understand in ...
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2
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828
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Measuring PWM controlled current with a microcontroller
I want to measure current using sensor MLX91220 which gives output in analog.
I have battery that I charge and discharge via switching MOSFET and want to measure current on this grid.
Problem is that ...
- 525
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4
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696
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Sensing voltage drop across the load in the H bridge
I use two BTN7970 to make a full bridge circuit. The load is a piece of shape memory alloy(SMA) wire.
I want to accurately measure the net voltage drop on the load excluding caused by mosfet's RDS. ...
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145
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Why should the fullwave current sensor bandwith be about 10 times switching frequency?
This is an example of high side switch current sensor in a buck-boost converter.
I read that for high-side switch full waveform sensing the current sensor bandwith should be about 10 times switching ...
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1
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168
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Bipolar high-dynamic range current sensing
I'm working on a project that will necessitate bipolar current measurement across a wide current range. It will need to accurately measure current from 750 mA down to 1 nA, although greater. The ...
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114
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Power outage detection to kickstart a safe shutdown and data retention process
I plan a system that operates on a 5v rail.
The power is supplied from an outside DC source.
The 5 V powers an RPI CM4 and other components that are controlled by it.
The whole system requires up to 5 ...
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103
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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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140
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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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716
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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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2
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2k
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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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665
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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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68
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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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758
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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 ...
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1
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403
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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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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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703
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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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253
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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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86
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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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69
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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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1
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2k
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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 ...
- 1,444
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2
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412
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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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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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139
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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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318
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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 ...
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901
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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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886
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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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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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382
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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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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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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 ...
