Explanation on Shunt resistor from meter

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Discussion Overview

The discussion revolves around the function and operation of shunt resistors in meters, particularly how they allow for accurate current measurement while diverting most of the current away from the meter coil. Participants explore the principles behind shunt resistors, their impact on meter readings, and the underlying electrical concepts.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants express confusion about how meters can measure current accurately when most of it is diverted away from the meter coil.
  • One participant explains that a meter shunt diverts a specific proportion of the total current, allowing the meter reading to remain proportional to the actual total current.
  • A numerical example is provided, illustrating how a meter with a specific resistance and a shunt resistor can determine the total current required for full-scale deflection.
  • Another participant suggests visualizing current division in parallel resistors and emphasizes the importance of Ohm's Law.
  • There are multiple comments addressing the tone of the discussion, with some participants feeling that remarks about intelligence are inappropriate.

Areas of Agreement / Disagreement

Participants generally agree on the basic function of shunt resistors but express differing levels of understanding and clarity regarding the explanations provided. There is also disagreement about the appropriateness of certain comments made in the thread.

Contextual Notes

Some explanations may depend on assumptions about participants' familiarity with electrical concepts, and there are unresolved questions about the clarity of the technical details presented.

Who May Find This Useful

Individuals interested in electrical engineering, instrumentation, or those seeking to understand the principles of current measurement in circuits may find this discussion relevant.

omerhassan
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I know meter shunts are used to direct most of the current away from the meter coil but my question is if you direct most of current away from the coil, how is the meter measuring the current flow accurately.

Im kinda slow in the head so no complex fried banana explanation. tnx
 
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Can someone explain this to be quick, or are you all also slow in the head
 
A meter shunt diverts an exact proportion of the total current away from the meter but also an exact proportion goes though the meter.

So, if it takes 1 amp to make the meter read full scale, it will take half an amp to make it read half scale. Similarly, the meter reading is always proportional to the actual total current.
 
omerhassan said:
Can someone explain this to be quick, or are you all also slow in the head

This comment is unacceptable. You can say what you like about your own intelligence, but it is insulting and outside Forum rules to assume anyone who doesn't choose to answer your question is stupid.

Answering questions is purely optional.
 
Vk6kro thank you, I don't mean stupid, I mean slow typers. But I still don't understand your explanation but thanks
 
Suppose the meter takes 1 mA and has a resistance of 900 ohms.
When 1 mA is flowing, the voltage across the meter is I * R or 0.001 amps * 900 ohms or 0.9 volts.

If you put a 100 ohm shunt across the meter, then the current through the shunt for a full scale meter reading would be 0.9 volts / 100 ohms or 9 mA.

So it now takes a total of 10 mA to get a full scale deflection on the meter.

Can you see that it takes 5 mA to get a half scale deflection on the meter?
 
Think of the meter as a resistor.

Surely you can solve how current divides between parallel resistors?Changing them to admittances helps visualize it.

Ohm's Law - it's more than just a suggestion.
 
omerhassan said:
Can someone explain this to be quick, or are you all also slow in the head

That can only be taken as an insult. "In the head" doesn't refer to typing speed.
Afiac, you can solve your own problems. Your main one is to learn to be polite when you need to know something and to apologise when you have offended someone.
 

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