Questions tagged [current-sensing]
The current-sensing tag has no usage guidance.
180 questions
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Can a 4 to 20 mA current loop be measured without using a resistor?
Background
There is an electrical system typically consisting of a 4 to 20 mA transmitter and receiver.
simulate this circuit – Schematic created using CircuitLab
So far, everything is working ...
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Designing a current sensing op-amp circuit for an AC load
I'm trying to simulate a current sensing op-amp circuit. My AC voltage, 24 VAC, is across a load of 10 Ω. I used a 100 μΩ resistor and measured the voltage across it using an op-amp.
Looking at some ...
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ACS71020-I2C data read problem
I recently working on ACS71020 with I2C communication .I will attach my module details, code and my results. The slave address of the I2C keeps changing and even If I turn on the supply the measured ...
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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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Sensing current down to tens of nA with INA828 or other OPA
I need to measure the current draw of DUT that can be an MCU in deep sleep, such as Attiny85, or a more power hungry MCU that is powered off by TPL5110. In this post, I proposed a circuit where an ...
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INA828 for sensing current down to tens of nA
I need to measure the voltage drop across a test resistor in order to sense the current flowing through it. This test resistor has a value of 1 MOhm and it's connected between the positive voltage of ...
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Window current detection through a current sense differential amplifier and a comparator
I'd like to implement a circuit to detect the over-current through a grounded load. The limits for that current are either 3mA DC current or -3mA and 3mA in case of bipolar AC current. I want to ...
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Makerbase TMC2226 stepper driver board: are current sense resistors underrated power-dissipation-wise?
I am looking at the schematics for Makerbase TMC2226 stepper driver board:
The schematic shows 1/8W 0.11 ohm current sense resistors.
The datasheet for TMC2226 IC says:
8 Selecting Sense Resistors
.....
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Can I use the existing current-sense resistor of LTC1473 for my own measurement?
I'm making a powerpath battery switcher using LTC1473. For its own inrush/short management, the LTC1473 uses a shunt resistor connected to its sense+ and sense- pins.
Since I also need the current ...
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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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Input Filter for Current Sense Amplifier - ODrive
Out of curiosity, can anyone explain to me why the input filters for the current sense amplifiers in the old ODrive schematics are unbalanced (i.e., the external resistor is only on the negative CSA ...
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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 ...
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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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How to sample current in high-kHz to low-MHz [closed]
I am working on a project that, at its simplest, is a switching circuit (either a half-bridge or single switch) connected to a resonant filter. I need a way to measure/sample the current going from ...
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Designing Eddy Current Sensor?
I am looking to build a eddy current sensor, I am having difficulty finding information on how I should be designing the sensor to fit my needs. There's a few studies and articles I've found that ...
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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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Common mode error formula from TI seems counter intuitive
I'm working on an application to measure current in a buck converter using a current sense amplifier. According to this video from Texas instriment, the equation for common mode error is same as eqn 1 ...
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Current sensing in DC-DC converter
I studied DC-DC converter in peak/valley/average mode control and I have a question about the methodology to sense the current in average current mode control. I saw lot of paper about DCR sensing but ...
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Troubleshooting Voltage Sensing Issues in Buck-Boost Chip Simulations
I performed a simulation on a buck-boost chip (LT8390). I understand that the sensing resistor placed between LSP and LSN is supposed to sense the differential voltage. This voltage is then amplified ...
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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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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 ...
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Sensing Resistor in Buck-Boost controllers
In the LT8390, there are two sensing resistors. The one connected to LSN/LSP is called RSENSE(Buck), and the one connected to ISP/ISN is called RSENSE(BOOST). To illustrate this more clearly, I've ...
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Allegro current sensors on 220 VAC mains
A friend is designing a power meter for 220 VAC mains and is considering Allegro current sensors like the ACS37002 or ACS71240. Those sensors put a wire with a sub-ohm resistance in line with the ...
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Unipolar stepper driven PWM to reduce voltage
I need to drop voltage for unipolar stepper motor with winding resistance 50ohm and inductance 40mH (measured with generator and oscilloscope for equivalent circuit Rout + (Rl + L)). Available Vcc is ...
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Current sensing nA to mA
I need to sense the current of a target MCU through various periods of its on/sleep/off state and then need to send this data back to another interface MCU to read out the value. They will be both on ...
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High-side driver current monitoring via microcontroller
I'm building an automotive power distribution module which makes use of the Infineon BTS50010 high-side driver.
The high-side driver current is monitored via the sense pin (IS) connected to a ...
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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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Inrush current on current sense resistors
The problem is on a circuit which implements PFC circuitry.
There are two parallel 0.36R current sense resistors located in the inrush current path. These resistors measure the PFC current through the ...
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High-side current sensing using PNP
I have the following three states:
State 1: When system is active with transducers, current through the load is approximately 350 mA.
State 2: When system is activated without transducers, current ...
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Choosing an adequate op-amp for shunt resistor sensing in SMPS applications
I would like to get some industry experts / design engineers opinion about potential methods to improve the proposed shunt resistor current sensing method below. The intention is to improve this ...
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Current-sense resistor switching mechanism
I planned to make a DIY power meter with automatic switch for current range, usually towards low (uA maybe) currents.
I came up with the design below to switch between various current-sense resistors. ...
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Understanding current sense circuit
I'm trying to adapt a current limiter design that I found, and I'm having trouble understanding the "current sense" part of it.
The current sensing is implemented using a shunt resistor, ...
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Flyback converter sense resistor placement and wiring
I am designing my first ever Flyback converter. The Fsw = 100kHz. Peak primary current = 3.26A.
The converter has to fit in a very small space, so I'm making a lot of compromises. For example, I could ...
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How to sense a varying current and voltage without affecting the load
I've been asked to build a circuit to switch a constant power (varying current & voltage) supply between two loads, for a research experiment the customer is carrying out. The loads are unknown ...
- 47k
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Issue with influence between channels in a dual-channel high-side current sensing circuit
I've designed a two-channel current sensing circuit integrated into a board that outputs two separate signals. However, I'm encountering an issue where one channel seems to influence the other, which, ...
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Is there a reliable way to sense RPM without modifying a spark plug cable?
I need to recreate a tachometer without altering the wire that goes to the engine spark plug. I can only modify the wiring intended to close the circuit to turn off the engine. It is necessary to take ...
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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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Is it wise to determine heating element temperature from resistivity?
Context
I'm making an electric furnace for melting metal, and aiming to make my own controller.
Everyone seems to just use thermocouples and a control loop, I thought perhaps I could just measure the ...
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Is it feasible to measure voltage drop across 0-ohm jumper resistors to determine excessive current draw?
We design very low-power devices which in standby mode use about 8 µA of current. They are powered by 3 V lithium primary cells and are designed to last for many years.
Every now and then we see a ...
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Need to understand the current sensor connection in this circuit
I'm working on creating a smart power meter for my home, and I found this tutorial. I want to understand each part of the circuit, and the tutorial covers everything. However, it doesn't explain why ...
- 473k
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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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High side, high voltage, micro ampere current sensing
I am working on a project in which I am required to sense current in micro ampere range from a 2 kV power supply. Here is a link of an article which I am referring.
https://www.analog.com/en/technical-...
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How do I make the circuit to sense the collector current for the FAN1100-F085?
I am trying to design an ignition coil driver using the FAN1100-F085 IC and a ISL9V3040x3ST−F085C IGBT.
I am having trouble understanding the datasheet when it comes to the current sensing. It says to ...
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How is this a current mirror?
This article is talking about floating an IC's GND to use it at a common mode voltage higher than it is rated for. It then says it level shifts the IC's current output to ground by using the Q1-Q2 ...
- 47k
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Current Transformer Current Sensing via operational-amplifier
This is a current sensing circuit, L1(CT2320) is a current transformer, U1 is generated by IGBT inverter ，U is one of a three phase of the motor driver voltage. I have several questions about this ...
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SCR falsely triggered on startup (battery low current monitor)
I'm trying to build a li ion low charge current detector and cutoff circuit as a complement to my battery charging setup. Charging should be disconnected when the current reaches 400mA or below. I'...
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Current sense trace vias underneath shunt resistor
I need to connect current sense traces from a shunt resistor to my PMIC on the other side of the board. Due to space constraints, I'd like the traces to pass through vias directly underneath the shunt ...
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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 ...
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LTspice simulation of a fluxgate excitation circuit with H bridge driver, Op-Amp and comparator not behaving as expected
Please see the following LTspice schematic:
This is an excitation circuit for a fluxgate current sensor. The inductor L1 models the magnetic core's B-H loop and dimension along with a sensing winding ...
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Current measurement with LT6015, simulation doesn't work
I'm trying to simulate high side shunt resistor current measurement using LT6015 op amp, but the simulation doesn't work I'm always having the same output even if I change the current. Can somebody ...
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