Questions tagged [current-measurement]

Measurements of the current flowing through a circuit

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2answers
46 views

Multimeter as a variable load

I want to measure the current that can be supplied from a lead acid battery I have. (To know it's remaining current supplying capacity). To measure current I need to connect a load and an ammeter (...
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3answers
93 views

Is current different across resistors in a voltage divider?

I know that this may seem like a simple question but I want to know whether the currents across the resistors of different values are equivalent. For example in the circuit depicted below, if I were ...
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2answers
45 views

LTSpice (windows) - current labelling

I want to measure current going into and out of an op-amp. However, when I do .op command, I am not able to understand which current is being referred to here. ...
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0answers
48 views

Need help with a solution for current measuring

I need a solution for measuring current through a load. It is a 15W load at 230 VAC or 24 VDC. I found the TMCS1100A4 from TI (datasheet). It's very nice because it can measure both AC and DC easily ...
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1answer
34 views

How to bypass current sensor (ACS712) default 2.5V voltage output in buck/boost converter PCB

I'm having a bit of trouble coming up with the most practical fix for my buck/boost converter PCB. To give a bit of an overview, I'm using a current sensor to read the current value through an ...
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1answer
39 views

An Integrator Reset Circuit not working properly

I am trying to integrate the output of a Rogowski coil , with an inverting integrator with a reset circuit. I want to have the voltage level 0V during the off time of my switch, however after reset ...
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1answer
26 views

I'm having issues setting up the LM13700 as a floating resistor and measuring the correct resistance values

So I'm still learning how OTA's work, and have an application using the LM13700 as a floating voltage controlled resistor as seen below: I'm using +/-12V rails for this circuit. I have it set up so ...
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2answers
64 views

Hall current sensor noise

For my project, I need to measure AC current for a 220V load (a more detialed description of the initial approach and problems can be found here. I'm using an ACS724 for +/-5A; the next step will be ...
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1answer
33 views

control dc dc converter board with the microcontroller

I want to control a bidirectional buck boost dc dc converter evaluation board evaluation boardusing STM32 Nucleoboard MCU. The evaluation board is having only I2C interface. I am connecting a 12V lead ...
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0answers
39 views

Current measurement USB to serial UART converter or Arduino

I want to perform a current measurement of an electronic module with the help of a multimeter with log function. Can I just couple the module to a USB to TTL serial UART converter and perform the ...
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1answer
61 views

Calculate the electrical current density (international metric systeml )

I have a doubt about a result on a result. I have to calculate the electrical current density like $$\frac{\,\text{A}}{\,\text{m}^2}$$ I have the following parameters: $$r=1\,\text{mm} =10^{-3}\,\text{...
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1answer
39 views

How to know the status of a two way switch through MCU

My project is this one that I asked earlier (except the fact that I'll be using SPDT switches) Two way lighting What I'm asking can the MCU detect if the circuit is closed (whether by the physical ...
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2answers
113 views

Programmable gain Transimpedance amplifier for 4-5 decade resistance measurement using Pulse voltage/current

As you can see from my previous question, I am trying to measure resistance within the range of 200k-60 ohms (around 4-5 decades). I will be using a pulse (5us pulse width and 50ns each rise and fall ...
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1answer
51 views

Advice regarding AC current measurement using a microcontroller

The goal is to design a simple and compact (as simple and compact as possible) module to perform AC current measurement (for one or two 220V loads) using a microcontroller. One of the issues is that I ...
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2answers
66 views

Raspberry Pi 4 won't boot with current sensor connected

I have a problem when trying to boot my Raspberry (c03111) with a current sensor connected. The Joy-it COM-KY053ADC is used to translate the analog signal of the current sensor (LEM Hass 50-s) to I2C ...
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3answers
126 views

Why is my multimeter stopping device from booting when measuring current?

I am using a BK Precision 2709B multimeter and attempting to measure the current of a device that runs off of a ~3.7V battery. The device boots up, initializes and then goes into its lower power state....
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1answer
108 views

Why is my multimeter reading such a high/erratic current?

Newbie to electronics here. I have a simple circuit consisting of just a 9V battery and an 820 ohm resistor. I was trying to measure the current with a multimeter (by opening the circuit between the ...
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1answer
65 views

Designing a current sense circuit to measure a wide range of resistances and noise considerations

I have an application in which I have to design a current sense circuit in order to measures the resistance of a load resistor that can have values between 200kohms and 60ohms. The input voltage of ...
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5answers
227 views

Accurately amplifying a number of current sense transformers

I've got 16 current sense transformers that are being used to monitor AC loads. The SCTs are current output type, producing 50mA on a 100A load. The maximum burden resistance is 10Ω, thus the voltage ...
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0answers
49 views

Ways to visualize current return paths on a PCB board

Overview I'm writing a paper on PCB layout, and included with the paper are some evaluation boards. Generally the boards demonstrate different layout concepts (bypass-caps, trace widths, controlled ...
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1answer
24 views

BLDC 3 phases low side current sensing

Hello I'm struggling with calculation of BLDC motor current. I'm using MP6540 driver for controlling BLDC. I can measure voltage (adc) and after using appropriate formula from datasheet I got current ...
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3answers
93 views

Determining current through a short circuit

Edit: So I have to calculate the current through the short circuit and what I thought of is: Applying current divider across 4kohm and then the 2kohm resistor right below to get their respective ...
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2answers
32 views

CD4052 multiplexer with different input voltages

I've been working on designing a PCB for my indoor garden and i'm facing a problem i dont understand. In my design i use a multiplexer (cd4052), to choose which sense resistor my current sensing chip (...
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1answer
28 views

MC34063A power consumption calculation

I'm designing a circuit based on the MC34063A switching regulator to step up 3.7V to 8V. The 3.7V for Vin comes from a 3.7V Li Ion battery and so I'm trying to calculate the battery life. I'm a bit ...
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0answers
26 views

Current Sensing IC (MAX9929F) Query

I am using a MAX9929F Current sensing IC and I have a question to someone to may have used it before, or may have some experience with these types of circuits. The circuit I built around the IC is the ...
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2answers
53 views

Asymmetrical output

I was searching for a current sense amplifier for measuring the current between a power supply and a battery i.e high side. I found the INA240A1 (evaluation module here). When I look at the ...
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2answers
39 views

Calculating DC motor rotations from current readings

Situation: I'm using a brushed DC motor to open and close the vents of a greenhouse and I would like to know the exact motor location for more granular temperature control. Motor moves at different ...
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2answers
157 views

Mains Power Metering

please see this schematics: Please look at the 3 transformers to the right of the picture (above the houses). They are current transformers. On the other hand, we have an SGM30C2 electrical meter. (...
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1answer
44 views

Voltage divider resistor sizing to minimise voltage variance

I've got the following circuit design simulated in SPICE, this is a copy of the EmonPi circuit design (https://github.com/openenergymonitor/emonpi/tree/master/hardware/emonpi/emonpi_V1_6). I've got a ...
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1answer
40 views

Hall effect current sensor ACS712 for battery application

I want to measure the current of 12V lead acid battery for charger application. So mostly, I need bidirectional current sensing.The current measurement can be done using shunt resistor or using hall ...
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0answers
70 views

Current sensor that works in 0nA-250nA range?

Is there any current sensor capable of sense very low current ranges from 0nA to 250nA? I would need to sense the current produced by this photodiode: GVGR-S11SD (http://www.geni-uv.com/download/...
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2answers
83 views

Switchable current shunt resistor

Looking at the reference design given for INA826 in the image below, what would my best options be if i wanted to replace J8 with something allowing me to switch in R19 (sense resistor) from a ...
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0answers
53 views

Can I use this circuit to control model trains with?

I am currently researching and developing several arduino/attiny projects for model railway applications. One of the projects is a method to 'catch' an analog train and gently slow it down using a ...
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0answers
33 views

Ion current measurement

I have a few questions: To measure the ion current in air plasma from a source that works in pulses, what method is best for ion current measurements? Is it by using a Rogowski coil or by measuring ...
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0answers
48 views

Analog current sensor design help needed

I have been thinking for some time about a circuit. I have been a digital designer for most of my career, and have recently begun studying analog again, and find it a welcome challenge. I am trying ...
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1answer
60 views

Find the voltage Vab and current of the circuit I

I was asked to find the voltage Vab and the current of the circuit I. I tried finding the voltage in ab using voltage divider, but I have two voltage sources and I don't know how to make the ...
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1answer
43 views

Correct arrangement of current sensing resistors for a BLDC motor?

I am designing the current limiting (fault detection) circuit for a three phase BLDC motor and I wanted to ask, If I have three switches on at any given time (180 degree commutation) than should the ...
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0answers
35 views

Offset of amplifier input voltage of shunt current amplifier

I'm trying to build a 20A E load and decided to use a 0.01Ohm shunt for the current measurements and set so I needed to amplify the shunt voltage by 10 using the "rail to rail" AD4522-2. At ...
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1answer
41 views

Using High side current sensor as a low side current sensor

I have a very small question to ask. Is it ok if a high side current sensor such as the MAX9929 be used as a low-side current sensor as well? Or should I look for some parameter in the datasheet. The ...
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1answer
43 views

Return path magnetic field on hall effect current sensor

We would like to use a toroid core and hall effect sensor shown in the figure below for measuring current in an Electric Vehicle from a battery pack. Questions are: Would placing the wire carrying ...
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0answers
53 views

How do i measure current in 10uA till 10A range in steps of 10uA?

I'm planning to build a circuit that measures the current from uA till 10A DC Line. Initially I thought of using HECT, but it is having better accuracy in higher current range. so I'm figuring out if ...
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2answers
69 views

Correct way to measure circuit power consumption before or after LDO

I have created a low power MCU project, and I want to measure the power consumption. I am confused with: a) the correct way to place the ammeter, before (picture A) or after (picture B) my voltage ...
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1answer
39 views

Id, Vds calculation

Simple and strange, looking at datasheet of BSS138 (Graphs) for this circuit below which is always ON Saturation mode Mosfet, Rds-ON = 3.5 Ω, VDS-ON = 0.1 V to 0.2 V. Id should be 16.66 mA but ...
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0answers
29 views

Inexplicable curve shape of short circuit current measurement on synchronous machine

I'm doing some experiments on a synchronous machine with follwing data: nominal power: 5kVA nominal stator voltage: 380V phase-phase nominal stator current: 7.6A nominal frequency: 50Hz / nominal ...
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1answer
51 views

Sensitivity of a sensor

I have a current sensor (sensitivity is 22mV/A) which is being used to measure AC current with its time stamp data. I have connected this sensor to an ADC (12 Bits resolution Can somebody please let ...
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1answer
80 views

Can you prove that electricity was generated by a photovoltaic cell?

I am wondering if it would be possible to build a photovoltaic cell that kept track of the electricity it generated (perhaps with a built-in meter), such that you could not trick the meter without ...
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1answer
84 views

Transimpedance amplifier oscillates

UPDATE: I have removed switch and shielded cables and improvised the board as shown in below image. The transimpedance amplifier is stable. I applied four signal of 10kHz, 1kHz, 1Hz and 100mHz of ...
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1answer
59 views

How to find the power supplied by the ideal current source? [closed]

In this question I have already found the current in the three meshes given using mesh analysis, they are (i1 = top mesh , i2 = bottom left, i3 = bottom right). How to find the power supplied by the ...
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1answer
43 views

Current loop receiver (minimal implementation)

I'm looking for a minimal design of a current loop receiver with the following characteristics: I_in 0-20mA U_in (-24) 0 - 24V. U_out 0 - 3.3V The precision doesn't need to be very high - an output ...
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5answers
337 views

Common ground in low side current sensing

I've asked this question a while back and user/Transistor told me that the circuit will be floating and drift without a common ground, he suggested a virtual ground. but in this case we already have a ...

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