Questions tagged [shunt]
Electrical shunt -- relating to a small resistance usually used to sense current. This is what your multimeter uses to measure current. This tag does not cover magnetic shunts.
203
questions
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1answer
36 views
Hall effect current sensor ACS712 for battery application
I want to measure the current of 12V lead acid battery for charger application. So mostly, I need bidirectional current sensing.The current measurement can be done using shunt resistor or using hall ...
0
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1answer
49 views
Killswitch: switchable high voltage path/shunt to ground without any additional power supply
I have a circuit with a high voltage source (rectifet 400VAC) (part of a
capacitor discharge ignition.)
High voltage should only be available if normal power (low voltage DC power supply for the rest ...
0
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0answers
22 views
Load/Shunt resistor value calculation for DC-DC Converters
I have DC-DC converter with rating -4KV and 1W. The unit supports current monitoring of output voltage. I would like to test the current monitoring using shunt resistor.
What should be the rating of ...
0
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0answers
29 views
current and voltage measurement circuits for battery [closed]
I want to measure battery voltage and current.
Lead acid battery 12V. The supply of the lead acid battery is dc dc converter. Here I need to measure the voltage and current and should be given to the ...
0
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1answer
83 views
Very fast short circuit detection
I am working on a high current MOSFET switch project. I would like to implement short circuit/overcurrent protection, that would be fast enough to prevent MOSFETs from blowing up. In the actual ...
1
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2answers
93 views
Measuring high-side vs low-side current, different readings?
simulate this circuit – Schematic created using CircuitLab
I'm measuring current consumption of several different handheld devices (calculators, flashlights, etc), at the [lithium] battery. ...
0
votes
1answer
36 views
How do you wire a transformer for multiple output and amperage?
I'm getting different answers watching the MOT (Microwave Oven Transformer) videos on YouTube. Some leave the shunt out, some leave it in, etc...
I have a MOT and want to make a 12VDC power source ...
0
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1answer
62 views
How to measure shunt drop with an Arduino
I'm looking at a schematic like the following:
simulate this circuit – Schematic created using CircuitLab
I understand that this will be a very rough resolution as the drop will be in the 25 to ...
1
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0answers
31 views
Can I use two AD623 instrumentation amps on one shunt to cover broader current range?
I'm working on building a circuit with an ESP8266 module. I'd like to track its current consumption over time so I've cooked up a scheme to use a microcontroller dev board (Arduino or something ...
1
vote
2answers
65 views
What is the best way to parallel two shunt resistors using a switch?
What kind of switch in place of SW1 will have minimum amount of error in current readings?
Max current is 10 A and we should be able to control the switch digitally.
simulate this circuit – ...
1
vote
1answer
35 views
Determining the shunt resistance for DRV8301 BLDC Gate Driver
I am trying to study how to drive BLDC (Brushless DC) motors, and got stuck in the current-sensing part.
I am using a DRV8301 Gate Driver IC, which contains with shunt amplifiers. My current ...
0
votes
1answer
69 views
Pulling down positive voltage to limit negative voltage current
Below circuit is the negative rail of a dual tracking power supply.
How do I detect voltage drop on Node1 and pull down Node2 to limit the current without using an op-amp?
Edit: I just want to define ...
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0answers
49 views
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0answers
61 views
Relationship between speed against armature current/torque in DC shunt motor
I do not understand why the graph is like this as below when we use flux control method of DC shunt motor
Also, can I change the x-axis of this graph to be armature current instead since equation of ...
2
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0answers
98 views
Why does my multimeter report a tiny current through a shunted 9-V battery?
Why does my multimeter report a tiny current (microamps, if that) through a shunt resistor (e.g., 1.5 kΩ) or even a short placed across the terminals of a new 9-V battery?
The multimeter and all ...
1
vote
2answers
76 views
BLDC 3phase motor. The resistor 5W 0.1 ohm to ground very hot when motor working at 250Hz
Any one help me on this my issuse.
I have a BLDC 3 phase motor controler similar to this Schem here encloses. When the motor working at 150Hz everything is ok. But if it is works at 250Hz then the ...
0
votes
1answer
63 views
Does a wide-band, high-current, inline ammeter circuit already exist?
I have an application where I would like to measure currents up to 1000 A, inline, but am also interested in using the same circuit for a low current part of the cycle. The thought is that if I can ...
0
votes
1answer
43 views
Which current types can be measured with a Shunt?
Which of the following current types are typically measured with the help of a shunt resistor?
DC
AC
Impulses (4/10 us, 8/20 us, longer impulses > 500us?)
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0answers
20 views
Current sensing, clearance, trace width
I have to design simple PCB that will measure current by shunt resistor(R7, R8, R9) and voltage by divider. Board has 3xin and 3xout for different voltage/current specifications. I have the following ...
1
vote
1answer
87 views
Shunt Burn Issue
I've this schematic, where I'm blinking output bulbs (21W @ 12VDC). Rate of blinking is 85 counts/min. The wave comes to be of 700ms. On time 350ms.
In this 350ms of On time, initially I skip 50~100ms ...
3
votes
1answer
69 views
Single shunt with multiple current sense amplifiers vs using multiple shunts
I would like to turn an Arduino clone into a current meter that allows me to measure the the power draw of a sensor node which has sleep and active modes. The sensor node's supply voltage is in the 4-...
4
votes
2answers
1k views
Is it practical to use relay contact resistance as a shunt?
I'm driving a DC motor and in its path is a relay with approximately 100m Ω contact resistance, can I use that resistance as a shunt resistor to measure the motor current?
I don't want to measure the ...
0
votes
1answer
57 views
Isolated DC-DC common mode choke without shunt?
I was reading a page on the Recom site (https://recom-power.com/en/rec-n-very-low-noise-filter-for-isolated-dc!sdc-converters-46.html?3) where they devised a filter setup to achieve very low noise on ...
1
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2answers
239 views
The issues of common ground with voltmeter and ammeters
Apologies if this post is, yet again, another noob in electronics. I have an engineering degree in audio but have newly found a passion for electronics and am teaching myself as I go.
I am trying to ...
0
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0answers
36 views
Comparator H Bridge current sense negative voltage input
I'm using lm339 basic comparator to sense current from an H Bridge. Current limiting was done somewhat successfully with acs712 after removing the capacitor from filter pin for limiting the bandwith. ...
0
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1answer
75 views
H Bridge vs Half Bridge current sense
Are there any disadvantages in measuring H Bridge current only via 1 shunt resistor?
Since it will be made by hand on a perf board the only disadvantage will be the possible longer wires that connect ...
2
votes
1answer
49 views
Low Side Current Sensing Grounding Question
I recently made a low side current sense circuit to test a power supply. It works well, but I am trying to understand the strange behavior that happens when I apply the negative lead of my probe to ...
0
votes
1answer
89 views
ADC Measure from source with higher voltage and different ground
I would like to measure the voltage of a battery that varies from 4,5V to 3V.
To do so I'm planning to connect this source to a STM32F4 DISCO board and one of its ADCs, which will be set to a VREF+ of ...
0
votes
1answer
73 views
Op Amp High Side Current Sensing
I'm trying to build a high-side current sensing circuit with a differential op-amp which can be seen below:
The LT1006 is actually an LM358 IRL(I know it's a peanut op-amp, but it's what I have ...
6
votes
3answers
935 views
Why cap across shunt resistor, input bypass caps and small resistors on current sensing inputs?
I want to build a sensitive current sensing circuit using shunt, and since I also repair MacBooks occasionally, I have some contact with the schematics of real working expensive devices (although ...
0
votes
1answer
109 views
Microamp-milliamp Measuring Circuit: will my circuit work? Feedback/Advice
I'm developing a device which must be able to measure milliamps and microamps on one of its lines (down to 1 microamp, but also clearly seeing if it's less than 1uA). It's going to be DC of different ...
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0answers
44 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 ...
1
vote
0answers
59 views
What is the value of this shunt resistor from a drone power distribution board?
What is the value of the shunt resistor shown below? It is from the drone power distribution board, rated for up to 120 A. I am guessing, that the value is 0.25 mOhm. However, even with this value, at ...
1
vote
3answers
133 views
Non inverted OpAmp & Shunt circuit not working
I am trying to measure the output from a Hall effect sensor (LEM-LF 310-S) for a welding application.
The maximum output of the sensor is 0-0.25A when sensing 0-500A. This range I need to convert to ...
0
votes
1answer
84 views
High Voltage DC - Shunt Resistor, Voltage Regulator Question
I'm a newbie here but was trying to wire a setup and was running into some issues attempting to calculate my required resistance, and resistor tolerance to current.
I have a power supply that brings ...
1
vote
1answer
149 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 ...
5
votes
3answers
2k views
How do I amplify the difference between two voltages?
Starting at the beginning: I have a shunt that carries DC current, and the voltage drop is very slight. I want to amplify it in order to see it better on oscilloscope, and to have it scaled correctly ...
0
votes
0answers
40 views
DC shunt motor electrical
A 5KW, 220V DC Shunt Motor draws 2A at rated voltage when running light. If the
armature and field resistances are 1Ω and 165Ω respectively, determine its efficiency
when running as a motor drawing an ...
0
votes
2answers
28 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
48 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 ...
2
votes
2answers
553 views
What is the purpose of clamping the gate and source of a mosfet
Is clamping the gate and source of a MOSFET really important? I have seen this in some articles and some datasheets of MOSFETs where they have built in clamping.
As far as i know they are used for ...
0
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3answers
72 views
Why don't we need to consider \$R_4\$ and \$R_5\$ when why calculate \$I_1\$?
My book said that \$I_1=I_T \times \frac{R_1}{R_1+R_2}\$,and \$I_2=I_T \times \frac{R_4}{R_4+R_5}\$
simulate this circuit – Schematic created using CircuitLab
I have two questions about these ...
0
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2answers
115 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
136 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" ...
1
vote
2answers
124 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 ...
1
vote
1answer
170 views
How to connect 50 A 12AWG cable to a shunt resistor in PCB?
I'm designing a PCB in which the current of a BLDC motor is measured through a PSG4NTEBL500F shunt resistor. The DC supply of the motor is connected to the PCB through a 12AWG cable and the circuit ...
0
votes
1answer
68 views
How to select shunt resistor value of the below circuit? We can use Ohm's law but I am still a bit confused
I am very new to hardware development. I am learning all the basics to design a battery management system for electric vehicles in the future.
I would like to know how to select a shunt resistor for ...
2
votes
3answers
311 views
large voltage spike over shunt resistor even at no load
I'm trying to build a stepper-motor driver. Each windig is driven as shown:
at the moment, im feeding this with PWNM signals of constant duty cycle, just to see how everything response. (PWMs are ...
0
votes
2answers
410 views
Wrong ground reference producing wrong output on ADS1115
I am currently working on a project, which involves measuring current in a DC circuit and storing that generated data on an arduino microcontroller.
I decided to go with the ADS1115 and a shunt, which ...
0
votes
2answers
74 views
Understanding purpose of a resistor in reference schematic TIDU034
Gents,
I'm analyzing this schematic, but do not understand couple of things. I would be grateful if someone could explain in detail these questions:
1) R6 - shunt? What's the purpose of it? Under ...
