Questions tagged [current-measurement]

Measurements of the current flowing through a circuit

Filter by
Sorted by
Tagged with
0
votes
1answer
49 views

Measuring the current of a small battery powered device

I am wanting to modify an existing battery powered device, to switch it on and off using a raspberry pi. To do this I want to make a transistor relay circuit. However, I need to know the current of ...
1
vote
0answers
40 views

Rectified DC current measurement using shunt or Current Transformer

I am working on a project to design a controller for battery charging solution. A 3 Phase delta power (440 Vrms ph to ph) is given to a 3-phase Variac Transformer ( Variac is operated ...
0
votes
0answers
28 views

Current measurement in MOSFET circuit

In this circuit, the drain current needs to be calculated when S1 opens and S2 closes and remain in this position for long time. In this position, the transistor is in cutoff region i.e Id=0. But the ...
0
votes
1answer
86 views

Can I draw more current from this battery?

I'm looking to build a power box like this one: The battery that I'll use is 12V 35Ah deep cycle battery, which has an initial current of <= 10.5A: Devices that I plan to connect are: On 12V ...
0
votes
0answers
30 views

How to measure the peak startup current for an electric motor?

How would I measure the startup current for an electric motor? For greater context, see https://diy.stackexchange.com/questions/194224/what-kind-of-inverter-do-i-need-for-an-inductive-load/194227?...
0
votes
1answer
41 views

Current Monitoring circuit setup and option exploration for IoT device testing

I would like to use the ADA4528 opamp or similar opamp to monitor current consumption across a sense resistor for an IoT device but with a Caveat. I want to measure the entire range with one setup/...
1
vote
0answers
24 views

What design considerations need to be made to accurately measure current flowing through a BLDC motor due to a 20khz PWM control?

My early attempts to incorporate current sensing onboard a BLDC motor drive operating at 20khz involved the MAX40201FAUA differential amplifier (50V/V) IC and a 0.001ohm shunt resistor. Results were, ...
3
votes
1answer
132 views

Value of resistor and the current in branch with the capacitor

I am trying to learn electronics basics. I have a question asking for the current in the capacitor branch and the value of the resistor that is before the ground I have used a circuit simulation ...
3
votes
2answers
89 views

What is the result of deviating from the Kelvin layout when designing a current sensing PCB?

For a two terminal current sensing shunt resistor with a layout that deviates from the symmetric Kelvin layout, what results should be expected? For example, with this layout, what result would be ...
1
vote
1answer
135 views

Current sense op-amp with integrated shunt vs expensive resistor

To simplify my question lets assume: I need to convert +/-7.07A RMS AC current into +/-707mV RMS voltage with high acurracy (0.1% or better). It may be also higher voltage, up to +/-2.5Vpk. For now ...
0
votes
1answer
37 views

How is the current measured in this setup?

I came across this article where they measure the current called leakage current, but they are not using an ammeter or DMM. I couldn't understand what(which device) they use to measure the current. ...
0
votes
0answers
24 views

LED driver - current monitoring AC or DC side with Arduino

I have 2 LED strips connected in parallel to the same LED driver (driver is constant current + constant voltage). I have got an Arduino controlling a relay module that switches the lights on or off (...
0
votes
3answers
52 views

How does the input voltage affect the current consumption of a microcontroller?

Is there a relationship between the current used by a microcontroller unit (MCU) and its input voltage? In other words, given a MCU with a wide-input range (e.g. 2.7 to 5.5V for the ATmega328P), will ...
0
votes
1answer
69 views

Current Sense Amplifier Potentials

I'm trying to implement a current sense amplifier in my application, but I have a question about setting it up with regards to current flow. Basically, in this case, you put a very small shunt ...
1
vote
1answer
36 views

Why is ngspice showing current as negative?

I have an extremely simple comparator circuit: The voltage at pin 7 goes into positive saturation when a positive input voltage is presented at pin 5. I'm simulating this using SPICE in KiCad. ...
0
votes
0answers
34 views

High side sensing of pulse current

I try to make high side current sensing from discrete parts (for understanding, this no commercial solution nor student project, just home stuff) for PWM motor driver (buck converter without LC filter)...
0
votes
3answers
111 views

Current Sensing on positive and negative voltage rails

I'm working on a design that uses two separate buck regulators to generate a positive and negative voltage, and I'm trying to implement current limiting with a current sensor. However, I am running ...
0
votes
2answers
27 views

Measuring current output of a diode driver

I have a laser diode driver chip that can produce DC currents up to 200mA. The current is adjusted by a potentiometer on the driver chip. The driver chip has four pins: inputs: GND, SUPPLY outputs: ...
1
vote
2answers
45 views

Calculating uncertainty in a current divisor

I had the following exercise to do for college: I designed an analog ammeter exactly like this: simulate this circuit – Schematic created using CircuitLab The idea is to design an ammeter ...
0
votes
1answer
45 views

Why is the load a resistive load, not an inductive load when I measure the current and voltage of the transmission line?

Question: Measure the transmission line of a substation. The relation between voltage and current is that the current lags the voltage for 180 degrees, so now I want to ask Which part of ...
1
vote
1answer
47 views

Resistor Divider Theory Check

I am using the LM5069MM-2 from Ti for a project. This project requires an over current protection limit. The LM5069 can do this and the data sheet shows how. But I don't understand the process Ti uses ...
1
vote
0answers
51 views

Non Inverting op-amp grounding

I have this LM358 op amp as a non inverting amplifier used for high side current control. I feed this ic with 5v on pin 8 and ground is pin 4. Pin 2 and 3 are the inverting and non inverting inputs. ...
1
vote
1answer
67 views

Strange currents in a lathe

I am playing with MCSA and Park's Vectors to value motors' health. As test bed I read currents out of a lathe Spinner TC600, and see something strange: Park's diagram is a snowflake (instead of an ...
0
votes
2answers
23 views

Static ICC calc with voltage regulator

If I have a power supply that is feeding a fully integrated voltage regulator(Lets call it VR) and so on the VR is feeding a chip. My goal is to calculating the static icc of the chip but I dont have ...
0
votes
1answer
35 views

Current decreasing while measuring the current through a constant current source resistor

My Circuit : The above is my circuit. The Forward drop of LEDs is typically 2.8V and a maximum of 3.15V. I designed the current through the string to be around 21mA, so the emitter resistor is ...
1
vote
1answer
35 views

Digitally measure current on very high voltage line

I would like to measure current to a standard CO2 lasertube, which is already possible with a battery-powered digital or analog ampere meter available for cheap, but these do not allow me to read this ...
1
vote
1answer
31 views

Difference between current sense amplifier filter configuration

I am trying to figure out what is the effect of the different connections of the C3 capacitor in this circuit. It is the classical difference amplifier configuration used in current sense with some ...
0
votes
1answer
32 views

Measuring servo torque

has anyone ever attempted to measure servo torque using current? Basically if you have a robot you want to detect stall state and approximate force being applied.
0
votes
0answers
50 views

high accuracy analog differential signal switching solutions to prevent distortion (relays?)

first let me define the application and circuit. the application of this is to sence currents ranging from 1nA to around 900mA. to accomplish this two resistors are used, a 10K for the nA range, and a ...
2
votes
2answers
45 views

Dynamic control of DC-DC converter current limit

I am interested in having dynamic control of the output current limit circuit of a DC-DC converter controller (the LTC3777 buck-boost controller in my case). This IC has a built-in current limit using ...
0
votes
1answer
92 views

Dual OP AMP setup circuit supposed to pull 2mA, but where is the other 4mA going?

This circuit uses half of the TI dual OPA2626 (not showing the other half of the OP AMP). This dual OP AMP supposed to use 2mA, but it's pulling around 6.8mA (measured at the Grnd pin and also at the ...
0
votes
1answer
38 views

Understanding this sensing approach

What could be the intent of the designer who made this? As far as I understand, if Vcc = 35V, when MOSFET is ON, actuator_sense pin goes to zero. When the MOSFET is OFF, the resistance L1 and R25 are ...
0
votes
2answers
39 views

Sensing solenoid current

I want to sense the current through a solenoid when it is ON. Ideally I would want this for testing purposes and overcurrent protection. As I have a free ADC pin in my microcontroller, I came up with ...
1
vote
1answer
62 views

Techniques for determining the peak of sine wave via ADC

From the book "Digital Protection for Power Systems" the author presents some algorithms to process a sinusoidal waveform. For example, below there's a fragment taken from the index. He also mentions ...
0
votes
1answer
107 views

Voltage Reference Resistor Calculation (Shunt)

I am trying to design a circuit using this LM4040-5 Voltage Precision Reference for my DAC8554, but I can't for the life of me figure out how to properly calculate the resistor value to be applied. ...
1
vote
1answer
42 views

AS8510 ADC Reading to Current/Voltage Measurement

I have this AMS AS8510 data acquisition IC for battery management with dual ADC (datasheet) that is supposed to measure the current, voltage and/or temperature of a 12 V battery. I'm having a hard ...
0
votes
2answers
98 views

Why does the voltage across a shunt spike then settle?

I'm using a 50 Ohm shunt to measure a current of about 50mA driven by a voltage of 110v 60Hz AC as a zero-crossing square-wave (with a step at the zero-crossing). Using my oscilloscope I can see ...
0
votes
1answer
49 views

Measuring wide range of currents with ADC

I'm designing an amplifier to read currents using a CT from 10 mA to 30A with a STM32 with no FPU. I have the following data: CT turns ratio = 1000:1 Burden resistor = 10 ohms ADC reference = 3.3 V ...
0
votes
1answer
97 views

How can I accurately and precisely measure current in a 110V AC circuit, with a 1kohm-50kohm load, using an oscilloscope?

I need to measure the electrical resistance of a volume of ground. To do this I need to cause a current to flow between two metal electrodes pushed into the soil (let's call them the "current" ...
0
votes
1answer
43 views

Alternatives to MID400

I'm trying to detect when 24vac is flowing between the "R" and "Y" terminals on my central air conditioner's thermostat using an Arduino Mega2560. I know from the answers to earlier questions posted ...
0
votes
1answer
54 views

Measuring current, instrumentation or differential amplifier?

I want to measure current at the high side of circuit with 0.1 mV accuracy using a 16 bit ADC. for sensing the voltage drop over a 100 mΩ 1% resistor I need to use an op amp which is cheap and easy to ...
1
vote
2answers
44 views

Experiment - measuring current across two resistors

My goal is to measure current at different points in the circuit. I took breadboard, D battery, two resistors and multimeter. Here is how my circuit looks schematically: Using multimeter I checked: D ...
1
vote
3answers
55 views

What is common mode voltage exactly in current sense amplifier ? how to select a current sense amplifier based on common mode voltage?

I understood the average difference between the input and output voltages is called common voltage .But still i have a doubt when it comes to current sense amplifier. i a m confused like is it the ...
0
votes
0answers
28 views

Device to measure current in the range of pico Ampere (pA)

I am working on an electrochemical quantitative sensor and considering the reaction rate I can predict a current output in the order of 10-1 pA (pico Ampere). I was wondering if there is any device ...
1
vote
1answer
28 views

Reading and writing analog voltages to two outputs of a lab bench supply from one microcontroller

I am planning on building my own lab bench power supply which should be software controlled and have two outputs. I am considering using the ATMega2560 due to its large amount of I/O pins, but I don't ...
0
votes
1answer
52 views

Which power supply to use for Raspberry Pi? High voltage Low current (10V, 1A) or low voltage high current supply (5V, 2A)? why? [closed]

As far as the official specifications are concerned an rPi can be powered with supplies from 5V to 12 V. Typical current for 5V supply is 2A. Total power required for an rPi is 10W roughly. Raspberry ...
0
votes
2answers
72 views

4ma-20ma loop from 0.97V to 2.75V

I'm trying to develop a 4ma-20ma loop from an 0.97(4ma)-2.75(20ma) input. This input comes from the output of a low pass filter of a PWM module. I've searched the web quite thoroughly but all the ...
1
vote
2answers
97 views

LDO quality with current measurement shunt

I'm designing a power supply block and need to measure the current flowing trough a LDO. It is clear that the current in front of the LDO and after the LDO are the same (apart from some tiny bit used ...
0
votes
0answers
23 views

Accuracy of a superdiode current transformer amplifier

I am thinking about this design (currently simulated in Qucs): to amplify and fully rectify a 60Hz signal from a current detection transformer, the ASM-010. It has an input range of 0-10A AC, and at ...
0
votes
0answers
31 views

Producing AC excitation current from microcontroller

See the current transformer below. Primary to secondary turns ratio is 1000:1, and Test winding to secondary turns ratio is 1:1. The burden resistor across the secondary is 10 ohms. I'm trying to ...

1
2
3 4 5
22