# Tagged Questions

Measurements of the current flowing through a circuit

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### Question regarding specifications of power bank for a laptop [migrated]

I'm not sure about how it suits the forum of electronics here on stackexchange, but I hope I'm at the right place. if not, please forgive and explain. So the case is that I own a high-end laptop (...
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### Doubt about current direction in CircuitLab

I'm not sure how to interpret the current value in this basic schematic. If you simulate it, CircuitLab will plot a value for the current flowing through the Output node. Why is it a negative value? ...
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### Input and output relation of ACS712 Hall effect current Sensor

ACS712 works by the use of the hall effect principle. When i went through the datasheet, i found out that the relation between input current and output voltage is varied largely ie. 66 mv/A to 185 mv/...
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### I want to measure the current of a +15/-15 digital signal, non-sine wave

I have a digital signal, similar to RS232, but at +15/-15. It is a non-sine wave and is used to also power DC motors and other devices (address coding, information, and power). I want to measure from ...
257 views

### Measuring current - shunt resistor or current transducer or something else

I have to measure current which is sine with 37Hz frequency 1350 mA(DC) + 190 mA(AC). The voltage in circuit is generated using PWM 27V, 600 Hz, PWM dithering adds alternating part of current. I want ...
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### Measuring Active power through current sensors

i want to measure the AC current - with 220 V AC 50 HZ at home - i will use a current sensor then find the power factor through comparing the signals of the V and I then find the power then i ...
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### 50A Accurate Current Sensing Circuit Design

I'm trying to design a current sensing circuit that can achieve a 0.01A accuracy across 50A DC. It is a battery powered brushless DC motor drive (battery --> current sensor --> controller --> motor). ...
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### current in circuit in transient state

simulate this circuit – Schematic created using CircuitLab The switch in the circuit is opened at at time t=0. What is the current through 10 ohm and 20 ohm resistor at t=0(-) and also when the ...
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### How I can test the power supply across the load?

I want to test my power supply at the 12 V 10 A specification. I had tried with connect a 100-watt 0.7-ohm load resistor across it, but by that time the voltage went down to 3 to 4 volt. How ...
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### Effect of damping resistor on its upstream?

I am struggling on understanding how certain function of circuit part affect inside whole circuit. There are two electron sources: 1. electrons generated from ionization by discharge (Plasma), 2. ...
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### A basic question on Current Flow, Voltage, and Power consumption

Background: Assume that I have Bulb that consumes 10 watts of electrical energy (power). The operating values for full brightness are: 5 volts, and 2 amps. Since Power(p) = Voltage(V) x Current(I) = ...
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### Current increases when circuit resistance is increased while measuring black box device power consumption

The circuit is powered with 3V a battery and contains a black box device who's power consumption we're measuring with a shunt. The rated required voltage for the device is 3V. Whit a 1 Ohm shunt, the ...
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### Calculating the power supplied by the current and voltage sources

simulate this circuit – Schematic created using CircuitLab I have attended one exam where I was asked to solve this Question. Generally the Power is nothing but the product of current and ...
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### Current at specific frequencies in a RLC circuit

Having been given a circuit, that has a resistance R of 4.0 Ω, an inductance L of 0.50 H, and a variable capacitance in series supplying a voltage V of 200 V at a frequency fr of 50 Hz, I have ...
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### A DMM low current measurement question

I'm stuck with a question when reading a textbook: The question is a situation as follows: The very high internal resistance of digital multi-meters, in their voltage measuring ranges, can be used ...
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### ACS712 Low Current Sensor

Before I begin, just to let you know that I'm new to electrical engineering, in case that my question sound weird to you, but here's my problem. I bought few days ago ACS712 Low Current Sensor and ...
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### How to measure micro and nano amps via microcontroller [closed]

The objective is to build/construct a circuit powered by an ATMEGA32 IC, using C++. This circuit will essentially be an ammeter for small current levels (10-6 and 10-9). I've done some basic points ...
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### By measuring the electricity generated, is it possible to calculate how fast the turbine was moving?

Say a wind turbine is moving at varying speeds. From the electricity it generates, would it be possible to calculate/replicate the motions of the turbine? How accurate can these measurements be? Will ...
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### DS2438 battery monitor: how to connect load

I am looking at the datasheet for the Maxim DS2438 battery monitor and am confused by this circuit diagram: How would the load be connected? If connected between battery + and circuit ground this ...
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### Resistance measurement using high side current sense amplifier

I want to measure very small resistances (0.5 to 1 Ohm) using a high side current sense amplifier. The device I have in mind is MAX9611. The typical application circuit from datasheet is like: My ...
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### Common ground between a current source and a power supply

I want to design a simple circuitry for testing a bench top current source through a load resistor. I want to use MAX9611, and read data through I2C by a micro-controller. The rough circuit schematic ...
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### High voltage DC current measurement by inductance?

I'd like to incorporate a few permanent ammeters in a 600V DC circuit. I've found all sorts of nifty panel ammeters, both analog and digital, but most are rated to less than a tenth that voltage. I ...
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### MPPT using pic16f877a (solar battery charger)

I'm trying to charge some batteries using 12v solar panels. I'm using a pic16f877a for the mppt algorithm(incremental conductance). I have two problems: 1)Current Sensing: I want to use acs712 (5A) ...
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### determining current in individual phase for a 3 phase winding brushless dc motor

I have an 3 phase brushless dc motor with no neutral wire. I measured the resistance from phase to phase and found them to be on average 0.255 ohms(between A and B, A and C, etc...all the values are ...
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### Low-side current sensing

I'm trying to build a brushless dc motor driver, which provides the possibility to measure the currents on all three phases of the motor independently. The driver IC that I'm using (DRV8313) has three ...
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### AC power measurement query

I'm trying to understand and tweak this smartplug reference design from TI. I'm stumped on the Metrology Analog Filters section on page 1. What I do not understand is why is there a 0R resistor on the ...
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### Measure current in power suppy [closed]

I have a power supply which I ordered online for 100 amps. I thought it will be digital but its an old fashioned type. I want to build the current sensing circuit to find out how much current is ...
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### Measuring DC current with Hall Effect sensor over PIC on the same circuit

Before I begin with my question just so you know I'm not very familiar with electrical engineering so please forgive if I ask some dumb question :) What I want is to know if I can use Hall Effect ...
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### practical design of integrator circuit with Rogowski coil

I am designing a current sensing device, using a rogowski coil.To give a simple explanation of the Rogowski coil, if I were to disregard parasitic components L2, R1, C1 and R2 the output voltage would ...
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### Why is bi-directional current sensing required in sensorless BLDC field-oriented-control?

For the past few weeks I've been trying to understand Field-oriented-control for 3-phase motors. Eventually I would like to implement one. I've gone through dozens of application notes from Microchip, ...
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### Current Transformer properties

I have a mains track (230VAC, 50Hz) on a custom PCB routed to multiple Solid-State Relays, and I want to measure the power going through this line. I'm looking into Current Transformers (CTs) to ...
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### How to measure 3phase RMS currents in PSCAD

I would like to measure 3 phase rms current as well as voltage of a load, In PSCAD 3ph rms voltage measuring block is available but there is no such block for current.
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### FET Current limiter 30A and overload detection

I plan to make a module for my motorbike to replace fuse by current limiters and overload detection system. I've heard nice things to do with J-FET. It should work up to 12V 30AMP. The detection ...
163 views

### How to make ammeter with arduino?

i'm interested to make ammeter from arduino. So, i have 70A/50mV shunt resistor and wiring it into arduino. From my schematic, Is this possible to meassure the current from 12V battery?If it possible ...
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### ADC error for low-voltage measurements

The application is high-side current sensing for a battery-operated device. The current drawn from the battery goes through a shunt resistor, the voltage across the resistor is amplified by an INA, ...
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### Effects of introducing offset in a current sense amplifier

I am working with the MAX9643 current sense amplifier in a configuration similar to this. I need to introduce a small offset in the output voltage. What are my options of doing this? Can I directly ...
210 views

### Current sensing at μA accuracy and ADC nonlinearity

Project context A battery-operated positioning device sends location information through GSM at regular intervals. Between the fixes, the device is in low-power mode. The battery is supposed to last ...
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### High voltage reading isssue

Here i am attaching old and new schematic for reference.While designing the old board i have made mistake keeping HV- (j14) as common ground reference . J14 and j12 are connected with high voltage 0-...
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### Current in a galvanic cell

I was looking through chemistry textbooks to find out how to determine how much current a galvanic cell should generate and what affects that current value. However, I did not find anything: textbooks ...
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### What type of fuse should I use for this basic electronics design?

I'm creating a simple Arduino project that utilizes a solenoid and a rotary encoder. I'm powering the entire device with a 12V 5A switching power supply. I want to add a fuse to the design but can't ...
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### why is the current of a aluminum-hydrogen galvanic cell low

I am having a galvanic cell with the following half cell equations: Anode--> 2Al(s) + 6OH --> 2Al(OH)3 + 6e- Cathode--> 6H+ + 6e- --> 3H2(g) I connected my cell to a 47 ohm resistor and measured ...
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### measuring a bad motor and large current spikes in a brush motor [closed]

I am new to this forum, I am an EIT and I have been tasked to implement a fixture to measure high current spikes on brush motors when loaded and unloaded. I am at a loss here as I have never ...
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### Rogowski coil with magnetic core

is it possible to use a rogowski coil with a magnetic core? ie i want to integrate the output of such coil rather to place a resistor on it. so, what is the differences between it and a current ...
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### What does the values or details mean? [duplicate]

You can see some values on all electronic devices like 5V,0.2/0.3A on mobile chargers.What do these values represent?what can we understand from them
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### Piezoelectric Voltage and current measurement across a 3.3kohm resistor.

I am testing a PZT 43 material with tapping sequence. The measurement of the material is: 10mm in length and 0.8CM in diameter. I am tapping the material with a plastic and holding it down with a ...
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### DC Fan using less than half of rated current. Looking to overvolt

I have a project involving a 200mm 12VDC PC cooling fan (FS-200RB) that will be used for cooling me - not a computer. The fan is labeled: 12V DC / 0.42A / 5.04W ...
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### current of a galvanic cell

I am having a galvanic cell with the following half cell equations: Anode--> 2Al(s) + 6OH --> 2Al(OH)3 + 6e- Cathode--> 6H+ + 6e- --> 3H2(g) So my cell is producing 6 electrons. Is there a way to ...
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### How to measure supply currents ranging from 1μA to 10mA?

I’m building a battery powered data logger with a microcontroller and several sensors. I’d like to measure the supply current of individual parts with idle currents in the μA range and peak currents ...