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.

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66 views

Why does the value of shunt resistor need to be very high for solar cell's greater efficiency?

In the circuit equivalent of a solar cell, shunt resistor is described as "The irregular polycrystalline lattice grain boundaries that resist to the flow of electrical current in the silicon ...
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46 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 ...
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22 views

How do I determine the S-matrix for a combined series and shunt capacitors circuit?

I need to compute the S-parameters for the following two-port circuit, with combined series and shunt capacitors. simulate this circuit – Schematic created using CircuitLab I have tried ...
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40 views

tweaking this circuit into a Over Voltage Protector (shunt regulator chip)

this is an example circuit from datasheet of TL431ACD, which is a adjustable precision shunt regulator chip. instead of the LED, can I use mosfet (or bjt+mosfet) to turn another regulator ON/OFF (...
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41 views

High current thermal bypass

I am using a shunt to measure the current on a 12V system on a boat. Most currents are very low (under 4 A) but when using the starter the peak current reach peaks of 250 A. I've sized the shunt to 50 ...
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68 views

Current sense resistor - Should I consider self-heating contribution?

I am trying to implement a precision current sense amplifier. I am calculating now the tolerances introduced by the resistor. I know the maximum drop will be 20mV and I will use a 5mΩ resistor. Max ...
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2k views

Resistor in shunt regulator not following Ohm's law?

I was reverse engineering a power tool battery charger (21V SMPS) that derives its 5V rail from a simple shunt regulator, employing a TL431 programmable precision reference and a NPN transistor, as ...
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97 views

creating a differential amplifier for low voltages (current shunt)

I'm trying to create a "precision" fully differential amplification stage, to measure uA on a 10R shunt, and mA on a 0.01R shunt. shunt resistance values are set at those values for burden ...
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71 views

Shunt resistor after MOSFET and op amp to amplify voltage

I'm trying to figurate out how to measure current in circuit. I have idea to use shunt resistor but after connecting op amp on shunt I have some unpredicted measurements on output of op amp. I want to ...
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46 views

Best practice for paralleled four leg shunt resistors connection to a shunt amp, and best placement

I am using three WSK12161L000FEB paralleled together on a four layer PCB for a three phase motor controller (9 shunts total in design, 3 for each phase) From my understanding, a kelvin connection to ...
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47 views

Limiting current with a shunt resistor

For my project, I am using a 3.3V source to run two motors. If the motors pull more than 1A, then they have to stop. I was told to do this with software and hardware protection. As a programmer, I ...
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43 views

Fixed voltage drop (current and temperature independent)

simulate this circuit – Schematic created using CircuitLab Is there a clever way to create a fixed voltage drop say 2V that is not affected by current or temperature? Voltage stability should ...
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2answers
73 views

Voltage stability factor of voltage regulation circuits

Here a shunt voltage regulator circuit with two Zener diodes. One Zener diode Z gives the reference voltage at the comparator given by T1 for the feedback signal out Ra-Rb potentiometer. I can't ...
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1answer
71 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 ...
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1answer
53 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 ...
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25 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 ...
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107 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 ...
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2answers
97 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. ...
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1answer
41 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 ...
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1answer
68 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 ...
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38 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 ...
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168 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 – ...
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44 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 ...
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84 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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110 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 ...
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99 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 ...
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78 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 ...
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1answer
69 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 ...
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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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24 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 ...
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1answer
91 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 ...
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135 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-...
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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 ...
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173 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 ...
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2answers
689 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 ...
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42 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. ...
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1answer
152 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 ...
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1answer
85 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 ...
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1answer
249 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 ...
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106 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 ...
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1k 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 ...
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1answer
190 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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73 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 ...
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99 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 ...
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3answers
140 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 ...
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94 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 ...
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1answer
176 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 ...
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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 ...
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45 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 ...

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