Measurements of the current flowing through a circuit

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36 views

Twisted pair for long distance voltage measurement

I want to measure the voltage drop across a shunt, but the ADC performing the measurement will be far from the actual shunt - perhaps five meters. I'll need to measure voltage drops across the shunt ...
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4answers
49 views

Measure indcutor ripple current in a SMPS

I need to measure the ripple current in a buck converter. In general, I add leads to the inductor and use a current probe. My issue now is that the inductor I am using has such a low inductance that ...
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2answers
38 views

Capacitor for current transformer measurement circuit

I want to measure an AC current with a current transformer and an arduino device. I found on a website ...
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1answer
53 views

the maximum and minimum output voltage of op-amp

my question is a bit specific, I have done the research but I got confused. I am trying to measure the current using current sense resistor and a current sense amplifier INA 210 . my measurements ...
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5answers
591 views

What is the difference between high precision resistors and current sense resistors

Actually, I am trying to build a current monitor for a wireless sensor network. I am going to use a current sense resistor as the current will pass through the resistor. By measuring the value of the ...
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1answer
49 views

Measure current of multiple loads with one sensor?

I have been doing some research for my project which requires to measure power consumption of 8 different loads. For that I plan to measure current in each line and multiply that with the voltage of ...
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2answers
89 views

Can I measure if current is on or off in cable with 24v DC (in a cheap way)

I have a number of valves that control the heating in rooms in our house. The valves have a pin on top which opens or closes the valve. The position of the pin is controlled by a regulator that sits ...
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1answer
50 views

How small should I make my shunt resistor?

I have a small multi-junction solar cell that I will be taking measurements of short-circuit current and open-circuit voltage periodically in order to approximate an IV curve for the cell. I have ...
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2answers
45 views

Can I drive a led light with help of a CT clamp

If I have a 230V wire with alternating current and a load in the far end, drawing current. Could you "steal" energy with a CT illustrated in the image, to for example drive a led light? BR Chris
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1answer
45 views

Switching mechnism

I am designing a power supply which has two output port. Only one should be selected at any time and given power (depend on if any one is connected to a load). I intend to use a current sense at the ...
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3answers
102 views

How to measure small currents using current to voltage converter?

The battery voltage = 12 volts. In the first circuit The op amp works as a current to voltage converter and its output equation is: Vout = - I * R I choosed R to be 20 ohm so that each 50 mA will ...
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2answers
46 views

Calculating AC power figure using the DC current consumption

In a system where I have 220V AC recitified/regulated/converted into 3.3V DC through a transformer and a voltage regulator, would the amount of current I will be drawing from the AC line equal to the ...
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2answers
57 views

Choice of current sensing reisistor

I need measure a 10A AC current, and need a 50mOhm current sensing resistor with tolerance <= 1% and good temperature stability. I find there are some choices, such as Vishay's RH,NH series, or ...
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2answers
35 views

Possible calculation error using current divider rule on a non ideal current source circuit

I am going through my notes in preparation to an exam, the following was taken straight from the board as my lecturer wrote it. As far as im aware the current divider rule should be $$I1 = It * ...
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1answer
45 views

Voltage regulator Current regulation

I want to understand the concept of current regulation in the circuit, In my research I came across the following link Boosting Regulator Current for IC 78xx by MJ2955 where in the circuit schematic ...
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2answers
106 views

Measuring uA current with DMM?

I'm wondering if anyone knows the accuracy of measuring uA current with a cheep (~25$) DMM? I need to measure some low power circuits (10-500uA) and I'm deciding whether I should get an analog uA ...
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2answers
77 views

Energy harvesting from a current transformer [closed]

Looking into developing a mobile GSM/3G/SMS current monitoring widget which measures and powers the circuitry from a current transformer(s). One of the major hurdles is gathering enough power to ...
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6answers
861 views

Why am I getting very different measurement results on a breadboard?

I have an AC to DC multiple output adapter. It has the following output: I set the voltage to 5V. When I measure the supplied current, I get 3.26A. Then I connect an output to it: When I ...
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1answer
56 views

adjustable IGBT current?

Goodmorning all, Here my very first question so I may be asking something that is may be already answerd but I couldn't find, My question is : How is current limiting achieved in modern IGBT based ...
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1answer
54 views

What determines the required bandwidth of current sensors in an electric motor drive?

Most motor drive control systems incorporate current feedback of some description. What determines the required frequency response or bandwidth of the current transducer? Is there any other ...
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1answer
85 views

Overcurrent protection schematic: is there any off the shelf solutions?

I need to protect my device from the flowing through currents above let's say 30 Amps. So I need a black box which will generate a digital signal if the current will be greater than specified (e.g. ...
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1answer
61 views

SPI consumes more power than I2C?

Does anyone know if SPI typically draws more current than I2C? The reason I'm asking is that I'm playing with the LIS3DH accelerometer and driving it with an Arduino. When I2C is used, the current ...
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1answer
49 views

How do I work out the total circuit Current?

I am trying to work out the circuit current so I can workout the voltages across my resistors but I don't know how to change the diode Which has a 0.6V drop into ohms so i can complete the formula. ...
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1answer
39 views

Calculating phase currents of an automotive alternator

I have an automotive (3-phase) alternator with peak rated output of 150A at 14V (after rectification, of course). How can I determine phase (AC) currents in this situation?
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0answers
37 views

LT6105 current sense amoplifier

I am using the LT6105 current sense amplifier Link. I am giving it a supply(Vcc) of 7V and the voltage to the Rsense is 5V. The Rin = 100Ohms and Rout = 4.7K. The schematic is - Now, based on the ...
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3answers
169 views

Possibly Incorrect Current Reading

I'm not entirely sure if I have done the following equation correct or not, but based on the calculations, my multimeter result seems to be incorrect. I have a very simple circuit, containing a 9V ...
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0answers
88 views

current sense circuit - High side sensing/Low side sensing

I want to measure the current through the 2 ohm Load resistor.I have read about high side and low side sensing.But I am confused about which method should I use in my case as the FETs are part of ...
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1answer
62 views

Current sensing with AD623

I want to measure current that flows from a several kΩ load with source voltage sweeps from 0-200V. I want to measure possible energy losses, so I need both low and high side sensing. Setup is ...
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1answer
115 views

How can one use the earth as a second wire?

I read recently that the earth can be used as a wire to save wiring costs. My understanding of how this works is that a power source, say a battery, separates charge, creating electrons on one side ...
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2answers
151 views

What's the most economical way to digitally measure 240V mains voltage, current and power factor?

I'm looking to capture and analyse measurements of the mains energy that I use per circuit. I've found a few consumer products that offer powerpoint energy monitoring such as the Kill-A-Watt, but PC ...
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1answer
67 views

Unexpected reversed voltage over shunt resistor

I'm trying to measure the current consumption of an accelerometer using a 1kOhm shunt at Vdd. I've read that there's a ~30kOhm resistor at SA0, so grounding it causes a much higher current draw. When ...
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2answers
51 views

High side current indicator/

simulate this circuit – Schematic created using CircuitLab Hi! I am in need to make a high-side current monitor for detecting whether load (R1) is present or not. As currents running ...
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2answers
146 views

Drawing current sensing transformers accurately

This is more of a stylistic question than anything else, but it important that the sketch be accurate to convey what is really going on. I'm wondering, how does one draw a current loop that is ...
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1answer
38 views

Level shifting in OPAMP and HE100T01 interfacing problem

Hi, I want to measure current of 0-50A. For that, in my application I am using HE100T01 hall effect sensor which can measure current from -100A to +100A(depending on the direction of flow it gives ...
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1answer
107 views

Shunt resistor choice for H-bridge current sensing

I'm trying to construct H-bridge using DRV8701 gate driver. This part expects you to attach low-side shunt resistor to measure current going through motor to limit your duty cycle if motor is stalled. ...
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2answers
77 views

Automation/Sensors: Reading electrical switchboard press for turning lights and fans w/o relays

To reduce power consumption I am implementing a control system that uses some computer vision to validate presence in a room and eventually control the lights & fans. For comparison purpose, I ...
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1answer
62 views

using a multiplexer for a high dynamic range current sensing

I am working on a project in which I am supposed to do current measurements for a sensor node. the range of the current varies from 0-30 mA the sensor node has two modes: 1. active mode (maximum ...
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2answers
83 views

How to tell when an LM334 is limiting the current?

I have an LM334 based constant current source configured to supply a max of 1 mA. The load has a variable impedance. My goal is to make an alarm of sorts when that impedance exceeds a threshold, and ...
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1answer
62 views

Measuring the amplitude of a sine wave

I want to measure the amplitude of a sine current signal (about 1kHz). The signal is of small amplitude, i.e. smaller than 50 mA. I suppose a simple rectifier is not accurate enough or even doesn't. ...
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0answers
58 views

Current-Voltage curve of Light emitting diode

Under Real time Applications of LED, I am getting negative current in forward voltage(mili volts)...Please tell me what is the reason behind this and how can i avoid it from getting negative current.
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2answers
72 views

Auto load limiter reverse power problem

Our generator is connected to grid by 33kv line. Due to some reason we supply a fixed amount of power to grid. This is done by a device named Auto Load Limiter Device which looks like It measures ...
3
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2answers
75 views

When to read Battery voltage and battery current during charging

I am using a micro-controller to drive a buck converter for Li-ion battery charging purpose(Micro-controller providing PWM to the buck converter). During charging the battery's current and voltage ...
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1answer
60 views

Why can't I simulate a current sensing IC (LT6100) using Proteus 8?

According to this image, I should be able to design a high side current sensing circuit with a gain of 10V/V using an LT6100: However, if I try to simulate this using Proteus 8 I get an error. Here ...
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1answer
21 views

Is there a way to measure current and fault current better than the ACS716KLATR-6BB-T

I need to measure 2.5A (ac) and detect fault current. Currently I am using a Isolated Current Sensor with Overcurrent Detection ACS716KLATR-6BB-T Datasheet I am using this part because space is the ...
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1answer
79 views

Non-contact mains voltage measurement

I am trying to develop a non-contact whole-house power usage monitor. I have reviewed jasonT's project, which uses AC clamps to measure current usage. However, from reading this post on how meters ...
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1answer
84 views

How to measure the current of a high voltage CO2 Laser?

The manufacturer of the CO2 Laser tube instructs to put an amp meter on the low side of the laser tube for calibration. While I understand the amp meter will only see a few milli volts above ground; ...
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3answers
194 views

How does a non contact voltage tester work?

How does a non contact voltage tester pen detect voltages and/or currents? Are they limited to voltages of a certain range or type (AC or DC)? Here's some experiments I have conducted that lead to ...
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0answers
24 views

Measuring and classify stepper motor

Hi guys I've got a little projet running and need your help: I am going to use a stepper motor and a motor driver, in my mind that should work (maybe with a heat sink for the driver). What do you ...
3
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1answer
70 views

Measuring current in independient circuits

I'm doing a project to monitor and control 5 separate air conditioner units in my house. The AC Units run in 240V power (two 120V phases), each unit has its own breaker in the box. I'm using five ...
3
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1answer
95 views

Current transformer minimum frequency

I need a current transformer for an induction heating project. After searching Digi-Key for a transformer meeting my specifications (turns ratio, current, mounting type, etc.), the cheapest model I ...