Questions tagged [current-measurement]

Measurements of the current flowing through a circuit

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4
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2answers
776 views

Designing a PCB that allows to measure current

What is the best way to "debug" the current in a PCB? My (first!) PCB has a 220v->5v PS on it. I would like to measure how much current is using after the PS to monitor how far from the ...
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1answer
93 views

Does the maximum voltage on a multimeter refer to the maximum difference between the two points or the difference between the points and ground?

I am trying to measure the current in a high voltage DC circuit (over 10 kV) and have an idea I think will work, but I want to make sure before I break equipment or create a dangerous situation due to ...
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6answers
1k views

Do you have to use an instrumentation amplifier to measure voltage across a 0.01 ohm shunt?

I was planning on implementing a current sense feature on the STM32 Bluepill to measure the current output of a solar panel (150 mA short-circuit current, 14 V Open-circuit voltage) using LM358 ...
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0answers
56 views

any recommendations for which Op-amp I should use to measure voltage across a current sense resistor?

I want to implement a current sensing functionality on an MCU (STM32F103 bluepill), but in order to read voltages across the shunts, I would need a differential amplifier to eliminate noise first ...
1
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1answer
31 views

Collector current in datasheet Graphs

Here is an example of output characteristics fot IGBT devices, i.e., the "collector current (Ic)-to-collector emitter voltage (Vce)" graph. Can somebody help me find what Ic represents here? ...
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0answers
19 views

Experimentally determining max current output of a power supply [duplicate]

I have a power supply with no real docs or labelling except a 3.3VDC label on an output pin. If I want to determine (at least roughly) the maximum amount of current it can put out over that pin, can I ...
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5answers
177 views

Where has this current gone in my current-voltage converter?

Everybody knows what a "current to voltage" converter is, a basic application configuration for op amps. This is a very level basic question. See the picture. What is wrong? Have I missed ...
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1answer
49 views

Bidirectional Hall current sensor signal conditioning (shift and scale sensor output voltage)

I am using a Hall current sensor in circuitry where I need to implement signal conditioning in order to improve accuracy of measurement. The Hall sensor outputs 1 volt when measuring maximum current ...
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0answers
33 views

Pcb trace width when connecting an ammeter and voltmeter together

After design and simulate my 2 channel voltmeter/ammeter with arduino I came across with an issue about trace width. This is an image with part of the circuit. On +VL and GND I will connect the load ...
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0answers
20 views

Estimating total amperage for multiple devices on a 120/208 three phase service

I've been poking at this question for a bit, and while I think I have the answer, I'm not entirely sure. I think I just need a sanity check from all the competing methods from coworkers. Assume I have ...
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3answers
70 views

Measuring Current in a PWM circuit

I am working on a simple project that entails controlling the power to a heating strip to control its temperature. The heating strip is not much more than a resistor with resistance provided by ...
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0answers
43 views

Difference in power consumption between ESP32 C3 variants

I am planning to choose between C3 mini and C3-Wroom. The main concern for me is the sleep current. I have confusion in the specifications. Is the specification provided here for the entire module? I ...
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0answers
27 views

Ground fault measurement in low voltage DC project

I am playing around with a system to detect residual current in a 12v DC system. Considering using this sensor: https://sensing.honeywell.com/index.php?ci_id=49794 If I run the +ve from the battery ...
0
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1answer
33 views

SP3485EN current consumption

I would like to size my source regulator for a circuit which contains the RS485 to UART bridge SP3485EN. How may I know the current consumption of the SP3485EN? Does it depend on the load? If it is, ...
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2answers
51 views

Measuring PWM controlled current with a microcontroller

I want to measure current using sensor MLX91220 which gives output in analog. I have battery that I charge and discharge via switching MOSFET and want to measure current on this grid. Problem is that ...
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5answers
1k views

Measuring current over longer period of time [closed]

I'm in the process of building a device based on the Espressif ESP32. The device will spend most of its life in deep sleep. With a simple multimeter I've been able to determine that it's using 0.25 uA ...
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0answers
35 views

Difference in Current Transformer Ratings?

I am looking at two current transformers, the SCT-013-000 and SCT-013-000V. (Datasheet for both) The SCT-0130-000 states that it has an output of 0-50mA, and for the V variant, it has an output of 0-...
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2answers
35 views

connecting current transducer to Arduino

I'm trying to measure an AC current on a wire using Rogowski coil based current transducer. the CT I have at home has output voltage of 5v and output current of 1A as specified in the datasheet here. ...
0
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2answers
56 views

Cheap voltmeter / ammeter installed to vehicle - common ground?

I have a cheap Chinese voltmeter / ammeter like the one shown below. I plan to install various 12V devices installed into my van, such as a 12V audio amp, LED strips, USB chargers, buck converters for ...
0
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1answer
62 views

Purpose of soft iron in a permanent magnet moving coil instrument

Why is the coil in a permanent magnet moving coil (PMMC) instrument wound on a soft iron core, even though we are dealing with direct current? Is it to avoid sudden increases in current, or because ...
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2answers
80 views

What do I measure to size a capacitor appropriately to soak up a pulse

As you may be aware, modern vehicles go to reasonable lengths to detect whether the various globes (indicator, headlamps, etc) have failed. I have a car designed for non-LED globes that sends pulses ...
0
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1answer
84 views

4 to 20mA interface technologies [closed]

I'm researching solutions for reading the interface. 4 to 20 mA. Today I only know the ADS1115 schematic solution below: What are the solutions for reading this interface in a professional and ...
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2answers
71 views

How to calculate the discharged current of a capacitor from the discharge curve?

I observed the discharge of a capacitor on an energy harvester chip via an oscilloscope. The Output was used to power a BLE module. I know the capacitor value, discharge time, and the top and bottom ...
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0answers
75 views

Current Capacity of Rectangular hollow copper bar

I have visited various site which include the table for current capacity of insulated wire and the busbar but no a single website gave the any particular equation or any calculation to measure current ...
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2answers
70 views

How to find the current consumed by an STM32 Nucleo-144 board [closed]

I'm trying to find the current consumed by ST Nucleo board for one of my applications to understand how it can be minimized on requirements.
0
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1answer
36 views

Measure a circuit (small system current consumption using power source

I am powering a chip (CY8CKIT-143A). It is a BLE module + micro-controller. I am using it to transmit the data of a thermistor. I am using a DC power supply (Agilent E3644A). I am powering the system ...
0
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1answer
61 views

How to current control for DC motor with PWM

I’m a student on a team developing this project. We are attempting to make an balancing system(by reaction wheel) with current and angle PID control. The whole circuit consists of dc motor, power ...
0
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1answer
56 views

Is the current on a 3-phase AC motor (mostly) identical across all phases?

I would like to monitor long term current consumption changes over time (and derive power if I know the voltage) on a 3 phase cooling compressor for a walk-in fridge. I am not 100% sure right now, but ...
0
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1answer
56 views

Does the quality of current transformers matter?

I would like to do some current sensing, i would like to know if cheap current transformers like the the SCT-013s as good as abit more pricier onnes on digikey, what should stop me from making my own?...
0
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1answer
51 views

Calculate mAh from logged current samples

I have designed a system that spends most of it's time in sleep and then wakes up to accomplish a very short task so it can return to sleep. Using a CurrentRanger, I have logged the current ...
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0answers
24 views

Calculating error and shunt resistor size for current sensing

I was going through TI training to choose what current shunt resistor to choose. I wanted to monitor my yacht 12V power systems. I have an INA3221 3 channel voltage/current sense board. How do I ...
0
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1answer
57 views

Data Sheet help: Current flowing through a MOSFET module

In a MOSFET module, when looking at the data sheet can I assume the current through each MOSFET device is the given Id, or is Id the current moving through the entire MOSFET module? For the data sheet ...
0
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1answer
75 views

Current meter doesn't short a circuit?

I have a control card where two pins can be shorted with a push button to trigger an action (5V can be measured between the two pins.) If I briefly short the pins with a jumper, the action is ...
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0answers
17 views

How to remove the noise current values during CT disconnected?

i am doing a energy monitoring system. i have done High pass filter in the values of ADC current and getting correct. but when CT disconnected some current(noise) getting how to fix it. device - ...
2
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4answers
355 views

Where I can find the actual current for my circuit?

I started from a very basic circuit. An LED, a resistor, and a power source. I need to choose a resistor to make sure the LED will not burn out (series circuit). My power source is WayinTop Breadboard ...
0
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2answers
51 views

Monitor a 5 A system with a compatible current sensor [closed]

I need to monitor a system that can consume up to 5 A of current on 5 V. Its components consume between tens and a few hundreds of mA each. A 10 mA resolution is acceptable. I need this monitor to ...
1
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1answer
26 views

How is the current drawn by a Peltier determined for a given voltage and given Th?

I have 12V 20A SMPS for building a cloud chamber. I have a question about configuring the Peltiers. I don't know how much current a Peltier draws for a given V at given Th (hot side °C) In my ...
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0answers
33 views

Unstable multimeter current readings [duplicate]

I have Fluke 17B+ DMM. When trying to measure DC current, the readings are constantly fluctuating. I tried first with a 9V 1A AC-DC wall adapter and the readings were jumping between 0.485 to 0.300 ...
1
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1answer
56 views

Multimeter effects on current flow [duplicate]

I am trying to measure the current flows over time of a Particle Argon from the initial boot, through normal processing then going into deep sleep mode. My code runs great on its own and does exactly ...
1
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2answers
68 views

Sensor output current vs voltage reading options for accuracy

I am trying to choose between two sensor output types. Either 0-10V or 4-20mA. I am using the INA219B to measure current right now but I am wondering if getting a different output sensor would be more ...
0
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1answer
80 views

how can I figure out if 1-3V is flowing from something using household items?

Basically what the (unconventional) question says! I don't have a voltmeter at home. How can I fashion one, or use some kind of test to determine if current is flowing? I know it's a relatively low ...
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0answers
51 views

Why do I keep blowing this current shunt amplifier?

I'm using an INA293B3-Q1 current shunt amplifier in the standard high-side configuration as shown below. The supply is a variable DC power supply (0-20V). Rsense = 1 mOhm. And, the load is a ...
3
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3answers
258 views

Microcontroller Analog negative input

For a circuit that I am designing I am going to measure DC current through a hall effect IC. The output voltage of this IC is small so I would like to amplify this with an OpAmp of some sort with a 3....
2
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0answers
90 views

amperes too low on this circuit

I'm trying to get the voltage between phases, the line current and the apparent, real and reactive power of the next circuit: but there are a few things dazzling me, the most important is why the ...
0
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1answer
67 views

Cost-effective current monitoring solution for PIC

I'm in search of a cost-effective solution for monitoring the current draw in a resistive heating element using a PIC. All of the Hall Effect sensors that I've looked into seem to output the same AC ...
0
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2answers
63 views

Non-inverting current to voltage converter

Using a single opamp with a resistor it is very easy to make a I to V converter, as shown in the diagram below. Note that if current is flowing from I_in towards ...
0
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1answer
87 views

220V current measurement?

I want to design an current protection circuit with current sense amplifier. I have to work with 220V 50Hz AC bus voltage. I could not find any IC or any design for this topic. Can someone give me ...
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2answers
68 views

In parallel current sources with capacitors

I have to get the correct equation of multiple parallel non-dependent current source in parallel with capacitors, as i seem to find the correct solution, the resulted simulation in LTSpice shows ...
0
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3answers
111 views

Why is 'density' different for current?

Considering an N-type semiconductor, when we talk about carrier density, it means number of electrons per unit volume. But, when we define current density(J), it is measured as total current per unit ...
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0answers
78 views

Circuit to measure current in high voltage, high frequency transformer

Next it is a simplified circuit diagram for high frequency transformer (50 kHz) which supplies a cathode-ray tube: Colored parts are intended to measure load current by ADC of microcontroller; ...

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