Questions tagged [current-measurement]
Measurements of the current flowing through a circuit
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2answers
50 views
Circuitry to measure sub-nano ampere current
Is there a well known methodology to design a IC circuitry to measure sub-nano ampere or even pico ampere currents within a very short delay of nano seconds? The SNR could be assumed to be fairly good ...
3
votes
5answers
117 views
How to measure micro watts (uW) [duplicate]
In an extreme low power project (MCU+BLE SIP running on a CR2016 battery for year(s)) I would like to measure the power consumption under different environments/algorithms.
What would be the correct ...
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0answers
45 views
20 kV 100 mA Voltage Current Sensor
like the title says, i need to measure 20 kV 100 mA line.
For the voltage part i found this:http://www.koncar-mjt.hr/en/docs/koncarmjtEN/documents/61/1_0/Original.pdf
and this:https://www.hivolt.de/...
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2answers
29 views
Use of UC3843BD1G for current measurement
I was trying to develop an accurate current measuring circuit. So I opened up a multimeter for some reference. In which I found this UC3843BD1G Current Mode PWM Controller. Can this chip help me in ...
3
votes
2answers
786 views
Current measurement op-amp calculation
I am trying to measure the current using sense resistor method.
Low Side Current Sensing method:
I am using shunt resistor in the low side, there will be a voltage drop across the resistor.
Since ...
0
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1answer
51 views
5V Current Transducer to 3.3V Analog GPIO Input
I am trying to find 3.3V variant of the 5V Current Transducer LTS_25-NP but so far no success. Is it possible to interface this 5V analog output to 3.3V STM32F407 analog input GPIOs?
1
vote
1answer
32 views
ESP32 using acs712 give wrong values
I'm trying to measure current with acs712 30A current sensor connecting to NodeMCU-32S but I'm getting wrong and unstable values. For zero current the ADC pin should read value of 2048 (esp has 12 bit ...
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2answers
43 views
Selection of External Current Transformer
simulate this circuit – Schematic created using CircuitLab
I am designing a product for motor protection circuit. where I want to use customized external CT for application which gives me ...
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1answer
68 views
What will be the current flows through the following circuit?
I`m confusing to see a textbook there is no current flows through the 7 ohm resistor. But why? And what will be the total current flowing through the circuit?
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1answer
22 views
High Power DC motor current control
I need to monitor a high power DC motor with 48V and 600A battery, if it's stalled or not (its a lift truck).
The driver is 25 parallel MOSFET with Rds(on)=7.6e-47 which control by 15kHz PWM.
I think ...
4
votes
2answers
562 views
Digital Current limiting with MCU
All current limiting circuits I've found until now use some sort of analog Logic with Op-Amps to limit/control the current.
(Why) is no digital current limiting used?
I would imagine a shunt resistor ...
0
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1answer
85 views
Voltage drop - Diode reverse biased
Can you please help me with this exercise?
In each circuit, calculate the current flowing through the 10kΩ resistor and calculate the voltage drop across the germanium diode. Please assume that a ...
2
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1answer
99 views
Significant DC current on precision DMM despite not being connected to anything
Disclaimer: I'm not a EE professional (I have a background in physics though), so please bear with me if the question seems banal, obvious or just plain stupid.
We have a Keysight 34465A DMM, which, ...
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3answers
52 views
Power determination for resistive load
I am a mechanical engineering student and i need to measure electrical output. I have some voltage and current measuring instruments. I used them to measure the voltage & current of a blower(...
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2answers
55 views
CB blew when trying to measure the current using multi meter. What went wrong?
I set my multimeter like this.
Plug the black lead to the short tab of NEMA5-15 receptacle first and the red lead to the long tab.
The moment I put the red lead in, there was a big spark. The ...
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0answers
56 views
Measuring current in the case of bridge amplifier at several MHz
Is there a way (or some chip) to measure current at about 5 MHz when the bridge amplifier is used? The output is a sine with amplitude 15 V. I need to measure accurately both amplitude and phase (the ...
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votes
1answer
40 views
How to measure current on low voltage/current brushed motor driven by H-Bridge?
I have a gearbox which transforms the rotational movement to linear movement. It drives a pin which moves back and forward using a DC motor.
I need to know when the pin reaches the two "end-stops" (...
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3answers
92 views
how to avoid brownout caused by a multimeter on esp32
I am using the VOLTCRAFT VC130 multimeter for measurement of current through my esp32. The microcontroller runs perfectly with two 1.5V batteries(~3V as read by multimeter in voltage mode). But when I ...
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3answers
64 views
digital current monitor/sensor for monitoring ~0.1 uA to mA current from a MCU and sensor [closed]
Hello I am in need of a current monitor/sensor like INA219 for monitoring current in the range of 0.1 uA to ~ mA. Kindly suggest a way to monitor current in such lower range.
I have a microcontroller ...
0
votes
1answer
66 views
How can I find the short circuit current across a and b?
In order to find R thevenin, I need to find Isc across a and b since there's a dependent source.
Based on my calculations, Vth=500/3V.
I've spent countless hours thinking about Isc,please help.
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3answers
118 views
Stall current calculation for DC motor
I'm trying to calculate the stall current for a 12 V DC gear motor (919D1481):
No load speed = 15800 RPM
No load current = 0.52 A
Nominal speed = 13360 RPM
Nominal current = 2.85 A
...
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1answer
39 views
How to measure small AC mains currents from a microcontroller?
I'd like to build a battery charger control circuit using an Arudino, a relay module, and a current sensor.
I'd use the relay to turn on AC power to a "smart charger" for one or more sets of lithium ...
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1answer
45 views
CT measuring circuit with PIC
I am using external CT to measure Current parameter. I am using PIC16F1938 to measure analog . Now here i am looking for circuit and calculation involved to get proper current rating
datasheet
Min ...
2
votes
2answers
59 views
How to measure small current waveforms using a uCurrent Gold and a mains grounded oscilloscope
I am attempting to use a uCurrent Gold as referenced by several SE posts such as measuring microampere current without noise with a mains-grounded oscilloscope, to observe the small current into an ...
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0answers
44 views
How to select current transformer
I want to build a system to measure and log current from 2 DC sources & 2 AC sources. Measurement range is 0.2 to 15 A. Accuracy needed is 0.1 A. Update rate is 100ms and AC source is 230V, 50Hz, ...
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votes
1answer
28 views
Estimate minimum current draw for a device
I'm trying to sum up the minimum current draw for all devices fed by a buck converter in order to determine the necessary inductance value. The max current is typically easy to find on datasheets, but ...
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vote
2answers
73 views
Non-intrusive measurement of current and voltage
Sorry if this question is too basic for this forum... I'm an interested amateur but far from a professional. I'd really appreciate information from someone more informed than myself.
Hypothetical ...
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votes
1answer
27 views
Control relay using split core current transformer
I have a YHDC SCT013-03 split core current transform which lists an output range from 0 V to 1 V for an input up to 30 A. My objective is to use this to open an close a contact switch.
The way I was ...
0
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2answers
39 views
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?
...
2
votes
3answers
1k 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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1answer
39 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
47 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
54 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. ...
1
vote
4answers
175 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
29 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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1answer
63 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 ...
2
votes
2answers
75 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
29 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
153 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
50 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 ...
0
votes
2answers
80 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 ...
0
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2answers
37 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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votes
1answer
67 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 ...
1
vote
1answer
88 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
78 views
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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1answer
42 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
75 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 ...
0
votes
1answer
137 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, ...
0
votes
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
votes
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 ...
