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Questions tagged [current-measurement]

Measurements of the current flowing through a circuit

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How to design aluminum alloy melting furnace with nichrome coil heater of 800 watt 26 swg coil?

I have 800 watt 26 SWG of length 9 meter nichrome wire and 220 volt AC supply. I want to heat nichrome coil up to 850C degree for aluminum alloy melting funace. How much current will I need? ...
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3answers
952 views

Measuring a small resistance, ~0.001 ohm

I have a low resistance resistor that I would like to use to measure the current through another circuit, but first I need to accurately determine its resistance. Its data sheet says it is 0.001 ohm +...
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19 views

Issues with calculating the minimum value of the Load Resistance (RL) in this scenario

I am currently in Year 12. I am facing issues with calculating the minimum value of RL before regulation stops in the following circuit: Below are the questions associated with this scenario: ...
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1answer
36 views

What is technical difference (internal voltage) between Digital multimeter's current measuring ranges mA (milliampere) and A(ampere)?

Is there any difference in internal power supply (DMM's) while knob turned to mA and A. While measuring current in my microcontroller-module with keeping mA on DMM, I am getting brownout detected (...
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1answer
45 views

How do i find Current Consumed by Circuit designed on Surface mount PCB without damaging PCB? [closed]

I have a circuit designed on PCB, and components (resistors, capacitors, diodes, Microcontrollers etc.) are all surface mount. I want to find the total current consumed by this circuit. I have traced ...
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2answers
46 views

Piezoelectric Project

I am currently working on project involving piezoelectricity and I'm in need of some advice. I'm pretty much a beginner, but I've been doing lots of research. I just need input to help fill some gaps. ...
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4answers
84 views

Ultracapacitors as a battery; how long will they last?

I would like a formula to be able to calculate how long it would take 6 2.7v 350f ultracapacitors connected in series to degrade from 14.4 volts to 11.5 volts given a parasitic draw of a specific load....
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1answer
22 views

In Parallel resonance circuit mentioned below, is current equal for Resistor and Inductor?

The parallel capacitor will have current leading voltage by 90°. In the case of Resistor and Inductor (which are in series with each other but they both are parallel to capacitor). Now, the upper half ...
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75 views

Extending the negative rail range for an Op Amp

I'm building a Transimpedance amplifier using the ADA4530-1 op amp by Analog Devices. I'm attempting to sense a fA current signal that is always negative and I would like to see if it would be ...
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1answer
50 views

How does this Current Comparator Circuit Work?

I have a quick couple of questions about this circuit: The schottky diodes are obviously for minimizing slew delay but how exactly do they do this? If the non inverting input is tied to ground and ...
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2answers
50 views

Switching a current source through a MUX

I have a current source of square pulses (0-20 uA) generated by a NI 9265 device. I am trying to build a fast switching circuit using TI CD4051 multiplexer to switch the current signal between ...
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1answer
27 views

Measure unknown load resistance on battery terminal

I need a method to measure the load resistance attached to the terminals on a battery. I want to determine this load before I turn mosfet on to let battery pack discharge. Most important I want to ...
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1answer
53 views

How do you measure quiescent current? [closed]

How do you measure quiescent current? (For instance, a Battery connected device)
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1answer
47 views

Effect of changing current sense resistor value in amplifier circuit

I am trying to implement a current output amplifier circuit shown below. Current is measured across sense resistor Rs to adjust input voltage Vin. Gain: G = -Iout/Vin = R2/(Gain-of-IA1*R1*RS) The ...
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2answers
33 views

TA12-100 Current Sensor (increase range)

I have a TA12-100 current sensor. The circuit have a 200ohm resistor as shown below. At 5A the analog signal hits the roof (1023). My question is - can I increase the resistor to be able to get ...
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2answers
34 views

Sense resistance based current sensing [closed]

http://www.carotron.com/articles/current-sensing-circuit/ http://ww1.microchip.com/downloads/en/appnotes/01332b.pdf https://www.arrow.com/en/research-and-events/articles/how-to-maximize-low-side-...
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1answer
55 views

How to calculate maximum amount of bulbs I can connect in parallel to match design specification of 1.5 A?

I'm designing a sensor triggered circuit that involves 220 V passing on a PCB, so I designed the board thickness to withstand a maximum of 1.5 A. The main load on the circuit would be a series of LED ...
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1answer
82 views

How can charging current be understood intuitively?

The charging current I’m talking about would be the one between un-shorted phases and ground when there is a short to ground in one of the phases in a distribution network or facility. I'm not talking ...
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2answers
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Why 7805c Voltage regulator drops the current if the current enters around 13mA to 7mA?

I know there should be voltage and current drop from the voltage regulator but my question is why current drops off ?
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0answers
29 views

PWM Switching and Current measurement

I have the following circuit: This circuit is created in simulink. It has a voltage source (Vs is 36V, Rs is the source's internal resistance, at 0.001Ω). Resistance R is 1Ω. I want to control the ...
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1answer
34 views

Measuring pulsating current using current sensor

I am measuring the current of the ignition coil using the hall effect sensor(ACS712)Datasheet. But the output of the hall effect sensor is pulsed analog signal. At zero current the output voltage is 2....
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0answers
60 views

Calculating collector current of NPN BJT with LED & resistor

I've been trying to wrap my head around the current I measured through the collector branch vs. the expected calculation for collector current and believe I have a knowledge gap in what to do. The ...
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1answer
101 views

How to ensure that an SPI master sends exactly 16 clock pulses to the slave?

I'm using this current sensor: TLI4970-D050T4 According to the datasheet: How can the SPI master send exactly 16 clock pulses to the slave, so I don't receive the 0's? When I'm reading this sensor, ...
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1answer
45 views

Nichrome wire temprature

I have recently been working on a project in which a material, whose ignition temperature is 500 °C, is to be ignited. So, what type of nichrome wire would be suitable for me, if I am using a 5&...
13
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9answers
3k views

In which scenarios is it important to measure microampere?

With the situation of finding a new multimeter, I found myself lost to the number of available devices on the market. For sure, to find the most suitable device I have to set some requirements. While ...
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3answers
55 views

Question on current sensor sampling

I'm using this current sensor TLI4970-D050T4 located at the emitter leg of a power IGBT. This transistor is being switched at 10 kHz. How do I choose the convenient sampling frequency for the sensor? ...
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3answers
47 views

Can a 24VDC 14amps rated power supply provide more current than it's rated?

I am having some problems with understanding power supply. Can a 24VDC 14A rated power supply provide more current than it's rated? I thought the maximum current the power supply can provide is 14A. ...
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2answers
48 views

Current Sensing problems in PWM-switching circuit

I have the following circuit: simulate this circuit – Schematic created using CircuitLab A simple voltage source is connected to a resistor. The current flow is controlled via an NPN switch. I ...
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1answer
66 views

Measuring change in magnitude of electric current due to change in conducting material characteristics

I posted this in the physics section. I now think this might be more appropriate section for these questions. I am looking for answers to the following: What is the order of magnitude of change in ...
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1answer
71 views

Use ACS712 current sensor in two-phase electrical system

I'm thinking about using the Allegro ACS712 current sensor for measuring house equipment current consumption (for example TV). The issue I'm facing is that my house energy supply is built around two ...
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0answers
92 views

Modify uCurrent Gold to read a higher current range

I'm using a uCurrent Gold (details here: https://www.eevblog.com/product/ucurrentgold/ and here: http://eevblog.com/files/uCurrentArticle.pdf) to measure some very low currents on a device running ...
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2answers
134 views

Overcurrent Sensing

I am designing an overcurrent protection circuit. I am sensing current with a LEM sensor across a sensing resistor of 16.5 ohm. The voltage drop for maximum current is 2 V. In the next stage I am ...
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2answers
55 views

Current drawn by a motor driver

Only interested in the binary logic part, not the motor side. The datasheet specifies a few absolute max ratings: Table 4. Absolute maximum rating IIN Input current (INA and INB pins) +/...
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1answer
50 views

FLUKE 15b+ fuse test

I have accidentally shorted my circuit (5 Volt Vcc) for approximately 1-2 seconds max. While the circuit was short circuit I use the FLUKE as ampermeter in miliAmper mode (400mA max fused) The current ...
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0answers
26 views

How to accurately measure battery chargers' in-rush current

I am using 2x RS3 Dualpro chargers in parallel for charging my batteries as seen below. RS3 Specs: AC Input: 100-240VAC 50/60 Hz 6.0 amps (Max) DC Output: 18 amps (Max) DC @ 12 Volts I have used ...
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0answers
26 views

LTC6102 - transient response, error of the simulator?

i'm building a device that has to measure current high side for 3 different scales: 1uA to 1mA, 1mA to 1A, 1A to 10A. what i'm doing is to use a current sense amplifier from Analog devices - LTC6102 (...
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1answer
44 views

Can I add an INA219 voltage\current sensor to this USB powerbank?

I have a Raspberry Pi Zero in a small robot that I have been powering off a USB powerbank and it works great. Unfortunately when the USB battery goes flat the power is cut and the Pi crashes. I want ...
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1answer
36 views

Neglecting certain elements in deriving the current of a series RLC circuit

The current at resonance in a series RLC circuit is described in the bottom derivation, along with it being plugged into the formula for finding the voltage across the inductor in the circuitw: I ...
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2answers
834 views

Simple Op-Amp setup for current sense has a strange working range

I am using a LM358D dual amplifier at the moment and my goal is to measure over-current on 2 motors. Before I'll be doing that, I made a test setup to test the equations and check the output signal of ...
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0answers
86 views

High-level (Ioh) and low-level (Iol) output current measurement on I/O pins

I'm looking for a procedure to measure the High-Level output current (Ioh) and Low-Level output current (Iol) in a I/O pin for a IC. I'm planning to use a variable resistor tied to VDD or VSS. Maybe ...
6
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1answer
613 views

Making a Hall effect sensor into a PCB

This question is related to Is it possible to “trace” a hall effect sensor on a PCB?. As far as I understand it, a Hall effect sensor consists of a metal plate, plus a current source and an amplifier....
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2answers
2k views

Seven-segment display seems to draw little current

I bought a 1.8-inch seven-segment common cathode LED display from AliExpress. So no datasheet available. I used a 1 kΩ resistor and a 5 V source, as to put a max 5 mA in the LED. I measured 1.6&...
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1answer
78 views

How to use a CT to measure overcurrent?

I plan to use a CT to measure the current on a resistor whose voltage will be controlled by two SCRs in antiparallel. The main function of the CT is to detect an overcurrent in the system to proceed ...
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1answer
81 views

Sense 230V - current

Brief sum up (you can go directly to the end if you already read the sum up in the other question) For a home project I'm making a controller to drive a two-direction 230V motor. For those unfamiliar ...
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0answers
34 views

low impedance as GND and current measurement, applied voltage sharing the same lead

(Image 1 is for the general idea, image2 is for questions 1 and 2, image 3 is for the 3rd question) In the setup shown below, the tuning fork is driven by an AC voltage source being connected to one ...
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1answer
95 views

Am I using my multimeter correctly to measure current?

I've wired up a simple circuit using: 9V Battery Blue LED 220 Ohm Resistor I was expecting a much higher value of mA? Is it true it's only 0.8mA? Shouldn't the LED light up, since we're closing the ...
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0answers
70 views

How to use a current transformer correctly?

I'm thinking of using a transformer to measure alternating current. My idea is to place a resistor in the secondary to produce a voltage and then it will be connected to an op. amplifier in voltage ...
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2answers
58 views

Current sense amplifier for high voltage (100-150V) low current (20 mA) application [closed]

I have an application where I need to measure the current on a relatively high voltage rail. The problem is that the current on the rail is quite low, only about 20 mA. Because of the high voltage, ...
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0answers
86 views

Advantages and disadvantages of voltage output vs. current output PMT modules

Context: I am building a custom right-angle static light scattering setup to measure aggregation of biomolecules in aqueous solution. I need the instrument to be as sensitive as possible, to allow ...
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2answers
65 views

Unexpected current reading when powering LED from ATmega328p IO pin

I would like my LED to run at 40mA (max current for ATmega328p IO pin). The LED datasheet says that 2.2V is max forward voltage. I am trying to calculate which resistor to use. According to the ...