Measurements of the current flowing through a circuit

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38 views

Interfacing Current shunt monitor with 16bit ADC

I am supposed to high side current measurement via shunt resistor (between source and load) and feed it to the microcontroller. For that purpose i have decided to use this IC MAX9922 which is a ultra ...
-1
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2answers
85 views

measuring current sense resistors [on hold]

I have a reference design circuit with 4 power rails. Already designed into the circuit are 4 high side current sense shunt resistors. What's the best way I can continuously measure the voltage across ...
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5answers
1k views

Ways to measure current in picoamperes

I need to check the low power consumption of a microcontroller in the range of picoamperes. I only have a multimeter capable of measuring milliamperes and as such it shows 0. Is there an easy and ...
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2answers
44 views

Why we want to convert a voltmeter to an ammeter or vice versa?

Why in laboratory experiments do we want to convert a voltmeter to an ammeter and vice versa? What is our main aim here that is for what we are doing it? If our goal was to change the range of the ...
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1answer
41 views

Which bypass cap position creates a cleaner voltage and current feedback circuit?

Is the following true? Caps = 2, 1800 uF Nichicon, Manf Num UHE1V182MHD3, CAP ALUM 1800UF 20% 35V RADIAL. "you want your bypass caps as close to what you are bypassing with the least series ...
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1answer
46 views

5 mA DC Isolated Current Sensor

We are trying to measure the presence of ~ 0-5 mA of DC current in an isolated manner (no shunt resistors). Are there any commercially available solutions?
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1answer
56 views

Insertion Resistance of Current Transformers

Given a current transformer like this: there is an insertion resistance that appears as a very small equivalent series resistance on the measured circuit. Since it is usually small (say, 0.0001 ...
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2answers
41 views

shunt current measurement with less voltage [closed]

Are there shunts available in market which can measure current of more than 200A but with voltage less than 50mV?
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1answer
42 views

Is there a formula for electric serial connection with different voltage/current?

I installed a Solar pad(24V/9A/220W) and connected to my grid-tie inverter. and I'm planning to install another, but due to space problem, I may not be able to add another panel the same size... ...
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1answer
36 views

How to calculate the current rating of different metal part (copper and brass) used inside a switch/socket/plug?

How to calculate the current ration of different metal parts normally used in household electrical appliance product like switch, socket, plug etc. How do i know that, the parts i have chosen that ...
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2answers
59 views

Wrong voltage in op amp circuit to adc

my circuit is not giving me the expected voltage. This is used to measure the current flowing trought the shunt. For example: if I expect 1.3, I get about 1,15V out. Anyone knows what I did wrong? ...
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2answers
33 views

Measuring low voltage AC current with a multimeter

I know that with DC you can measure current by putting your meter in series with the positive supply. I have a project running off a low voltage AC supply. Can I do the same?
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1answer
35 views

How to properly compute device need and set of a Universal adapter for powering said device [duplicate]

So, I just blew the fuse in my 17" monitor using a universal adapter with the settings Input: 100-240V 1.5A(1.5A) 50/60hz Output: 15/16/18.5/19.5/20/22/24V (max of 70w) I want a clarification of ...
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1answer
43 views

why is my differential amps error related to load impedence?

So ive built up this circuit, as a simple current limiter. After making sure the output is null when the differential is 0, i get different errors depending on the load impedance even when the both ...
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2answers
104 views

Measuring very low current

I have asked here a month ago regarding measurement of very low current. I was told that Amper-Meters today has this resistance in series that will cause a voltage drop, hence you can't measure a very ...
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1answer
28 views

Feedback Gain Loss of Transimpedance Amplifier

I have designed a single-supply (3.3V) potentiostat that initiates electrochemical reactions, converts the generated electrochemical current into a voltage via a transimpedance amplifier (op-amp used ...
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1answer
38 views

Clamp Meter Working Principle

Basic theory of clamp meter to measure rms of current wave. What I have in mind is that wire creates the changing flux that induces voltage in the meter.This voltage is calibrated ? Also how does the ...
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1answer
86 views

Attenuation of Input Signal

Schematic Simulation Model The circuit is simple , it includes a 3mA Sine Current source in parallel to a Resistor that converts it to voltage and supplies it to the differential amplifier with ...
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2answers
33 views

Estimating battery capacity remaining from SLA connected to motors

I have an SLA battery, at say 10 Amp-Hours, connected to 3 high power motors. Each motor can draw up to 10 Amps each (worst case / max power). Using Q = It as an ...
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3answers
61 views

Sign of current through a voltage source

simulate this circuit – Schematic created using CircuitLab I am a total newbie to circuits, so please forgive my naivety. My question is the following: When I simulate the above circuit ...
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1answer
45 views

Current monitor shows overload even for small load

I have a current-shunt monitor using INA202 between a 5V power supply and loads. The current monitor should turn off a MOSFET switch and disconnects the loads if the load current goes over 150mA. I ...
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0answers
19 views

Current harmonics measurement for building automation and energy monitoring

I want to measure current ranging from 1mA to 30 A approximately. I want to use both shunt(low resistance current shunt) and rogowski coil. The shunt is for large currents and the rogowski coil is to ...
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3answers
158 views

confusing current readings

I know that Ohm's Law is V = IR but I am getting some very confusing current readings from multiple multimeters. Here is my very basic breadboard configuration: V = 6v R = 200 Ohms I = Should ...
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1answer
152 views

Measuring currents between 100pA to 100uA

I want to measure absortion/resorbtion currents of dielectric when applying 1000V, 1500V, 2000V. I have made a small currents measuring device using a LOG114: I use : LOG114 with 1uA reference ...
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2answers
281 views

Measuring current drops voltage?

We have some pcb in which contains an MCU ,and some WiFi module . Usually at start, the board takes 70-100mA with 3v3 . It gets its current from the UNO board connected to a mac. It works great like ...
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1answer
49 views

Avoid heating with high current

I am new to electronics and just tinkering with it first time. I have laptop charger with 19V/3.42A and connected to 12v regulator and 3.3v regulator to get two voltages - 12v and 3.3v. I am going to ...
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1answer
72 views

Understanding a current sensor circuit

I'm struggling to see how the output of this circuit is $$V_{0} = {I_{s} R_{s} R_{L}/{5k}} $$ My work thus far: I understand the voltage into the base of the BJT is $$I_{s}R_{s}$$ I understand the ...
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1answer
103 views

Circuit to detect amperage?

Is there a circuit which can detect how much amps are flowing through it, and if the amperage falls below a certain level to output some signal? (e.g. to direct the voltage to a different output) ...
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1answer
108 views

Driving IR LEDs using PWM - measuring current & current source questions

For a project I'm currently working on, we're trying to drive 940nm IR LEDs (Kingbright L-934-F3C) using PWM, regulated by an Arduino Uno. We've run into several issues during our prototyping process ...
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1answer
53 views

Problem Measuring Current in a High Voltage circuit with arduino

I 'm measuring a current in a resistor as shown in the picture below. There I'm using a voltage substractor with an LM324 Operational Amplifier. I'm having trouble in the real World when the voltage ...
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1answer
39 views

12Vdc 5A Power supply electricity consumption [closed]

i am using a 12Vdc 5Amp regulated power supply to power some Led lights.The total consumption is 2Amp. I need to understand if the power supply consumes less electricity(230Vac) if i do not use all ...
0
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1answer
131 views

Measuring AC voltage (0.333vac max) using a 10 bit ADC on Atmel ATMEGA328

new to this so please be kind. want to measure AC current in domestic supplies using an atmel ATMEGA328P chip wit the best resolution possible I need to use the split core current transformer ...
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0answers
31 views

3 channel vs. 4 channel 120/240 power meter

So I live in the US, where we have center tapped power for residential use, with two hots and a single neutral wire. My question is what would be the potential effective difference in power ...
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2answers
357 views

Could you explain how this current measurement circuit works?

I have a schematic for current measurement, but I don't really know how can I calculate the output of it. The op-amps are on +-12V. The output of the circuit is 0.2*I(Rs) [V] (--> this is what I don't ...
2
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1answer
52 views

Protecting current measuring shunt resistor from overcurrent

To measure the current "drawn" by a 12V PTC heater element and to be able to switch it on and off from an AVR micro controller, I have come up with the circuit below. The PTC heater element has ...
2
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2answers
46 views

How responsive are current transducers?

We are using an (XD-V5-01) to measure an AC current but what we are not sure of is how responsive devices like this are. Do they accurately reflect the current being measured instantly (100-200 ms)? ...
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2answers
158 views

Oscilloscope measuring current that flows a few milliseconds

Is it possible to measure current that is flowing for 2 or 3 milliseconds inside a circuit through oscilloscope by measuring the voltage drop across a resistor ? The supply voltage is generated by ...
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4answers
128 views

Sensing current upto 2A w/ high resolution

I'm trying to sense a current that will flow in a motor (current shouldn't exceed 2Amps), and I'd like to have a high resolution on this measurement. I was hoping on using the ACS712, but it says the ...
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5answers
369 views

Measuring a huge resistance on low voltage

I was thinking on this theoretical experiment for a while, but nothing useful came into my mind. We have a "resistor" (rather a material like plastic) with a resistance expected to be very high, say ...
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1answer
51 views

Regulate and verify an AC current to test a current transducer sensor

Firstly my background in software so this is a bit of foreign territory for me. I have the requirement to monitor an AC current between 0 and 3 Amps. The plan so far in to use a non invasive current ...
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2answers
58 views

Current measurement on low resistance sources

Most of the devices to measure current at micro amps level or lower recommend a input resistance of more than 1kOhms. (As for an example , shorting the ammeter leads, which is essentially what happens ...
0
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2answers
58 views

Voltage on the secondary of current transformer

We know that current transformer is used to step down the current of the primary side. So basically it is a STEP UP transformer. Also we say that current transformer basically works on close to short ...
2
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2answers
130 views

Current Shunt Vs Current Clamp Meter - 15% difference Which one is right?

I have a variable AC power supply. 0-12V 0-1800A 60hz. I have always been told to trust the current shunts and not current clamps when measuring current. The current clamps are supposed to accurate ...
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3answers
67 views

What could be the voltage of this common DC motor? [closed]

Below is the picture of a common DC motor usually used in electronic toys. This motor is quite common so I guess someone may be knowing it's voltage and how much current it draws. I could've tested it ...
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2answers
57 views

Power measurement on neutral instead of line

what is the advantage or disadvantage of measuring the power on neutral insted of line in a single phase wiring. Generally I have observed that metering chip is given input from line to its Vin or ...
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0answers
84 views

Current sensing in H bridge for Stall detection-Purpose of Diode

I have a circuit, which is powered from two 1.5 V AA battery. It has a MCU and PNP - NPN Hbridge for driving motor. The motor (RF-300CA-11400) datasheet is here in this Link. The Motor will be turned ...
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2answers
59 views

How do I determine my burden resistor for my current sensor?

So I've got a -12v +12v ADC input limit and I've got a 200 turns ratio current transformer. My input Max current is 30A which is stepped down to 150mA. How do I determine the right burden resistor so ...
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0answers
36 views

current feedback design

How do I select the current sensing resistor \$R_{56}\$ with following details: Feedback threshold voltage is 0.5V. DC input voltage 400V. AC output voltage 230V. output power is 500W. operating ...
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2answers
127 views

DC non invasive power measurment

For one of my PhD project I have to measure power consumption from different electric wheelchairs during various tasks and recor these measurment for later studies. I have not much experience in ...
0
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1answer
76 views

Measuring current using low side shunt method (MCLV-2 board)

I am trying to measure the current through the MOSFET switch M1 using low side shunt resistor method (on MCLV-2 dev. board). I can read the signal `Vout' on the analog input of a dsPIC33F MCU. I ...