Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [current-measurement]

Measurements of the current flowing through a circuit

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Why am I not dead after repeatedly touching a high-voltage source?

While playing with mosquito racket in my home, I unscrewed the racket and touched the 2 wires with my hands. I felt that my bones were dislocated, I got shocked, but I am not dead. My calculations say that I should die: the output voltage is 5 kV to…
pankaj prasad
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What is the usage of Zero Ohm & MiliOhm Resistor?

I am new to PCB design and I noticed that some schematics use 0Ω or 100mΩ resistors. What is their purpose and why do we need to use them in our PCB design? Normally if we wish to probe how much current the load is taking, we put a jumper pin across…
Dennis
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How do I measure 10,000 A DC?

What is the standard way to measure a current of about 10,000 A? DC clamp meters seem to have only scales up to 2,000 A. Edit Some background of this question: I am a high school physics teacher and I am trying to improve some classical experiments…
Julia
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7 answers

How do I calculate the power rating for zero-ohm resistors?

Based on my earlier question, since there supposed to be zero voltage (V=IR) drop across a 0 Ω resistor, how do we select the power rating of such a component? For example, let's say I were to connect a zero-ohm resistor in between 5 V power source…
Dennis
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What are the advantages of a shunt resistor vs. a hall effect sensor?

I'm constructing a boost converter, and I need to measure both the input current and the output current. Currents range anywhere from 25A to 200A, depending on the model. My controller is referenced to the negative rail of the converter. I've been…
Stephen Collings
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What is the difference between burden resistor and a normal one?

I just came across the word 'Burden Resistor'. Is it any different from a normal resistor? If it is different, where can I possibly get one? Sparkfun hasn't got one listed. Any help is appreciated. I am trying to build a current sensing circuit.
Daniel Euchar
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What value does ammeter or voltmeter measures (RMS, Average or Peak )?

What value does these meters measure? Is it RMS, Average or Peak value ?
Arun M
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Is there an implicit "unit of time" involved in electricity measurement? (e.g. miles per hour, kb per second, amps per ???)

I'm very new to electronics and I am going through what must be a common difficulty in grasping voltage, current, and resistance. I'll restrict my question to current as I suspect understanding that piece may shed light on voltage and…
Cliff Pruitt
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8 answers

Finding the resistance of a resistor without multimeter

So this is a trivial but frustrating issue I’ve come across. I have two 5 band resistors and I am having a hard time differentiating the tolerance band. I don’t have a multimeter on me and I don’t know if these are 1k (Brown black black brown brown)…
Jake
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2 answers

Seven-segment display seems to draw little current

I bought a 1.8-inch seven-segment common cathode LED display from AliExpress. So no datasheet available. I used a 1 kΩ resistor and a 5 V source, as to put a max 5 mA in the LED. I measured 1.6 V for the decimal dot, and 3.5 V for each segment. The…
mathieu
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Why use an input resistor in this current sense circuit?

In the Linear Technology AN 105 on current sensing one can find the following circuit. I am wondering what the purpose of the 200 ohm resistor on the inverting input is. It appears to have no effect. Note that in the following paragraph a virtually…
Max
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How to plot current in ngspice?

I wish to plot out the current and power in ngspice. In the case of voltage, for example, if I wanted to plot the voltage at node 1 I would use: plot v(1) Problem is, when I try i(1), the vector isn't recognized. Could someone provide a few…
sj755
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Why don't hall effect current sensors exist for low currents?

There do not seem to be hall effect current senors available for small currents, say on the order of 500mA. I'm guessing this is due to some technical or physical limitation. What is it?
Phil Frost
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Why would a current measurement shunt design use 4 sense pins?

I am interested in low resistance shunts (tens / hundreds of microohms range) used in high voltage / high current setting. Typically, those are busbar-mounted shunt resistors like this one: The current is passing through the busbar and the shunt,…
Dainius Stankevicius
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Why does a multimeter put more voltage to measure a smaller resistance?

I noticed this behaviour on two different multimeters (different models and brands as well). At first I did not put a multimeter in the way to measure how much voltage changed for the different scales of the meter: I realized that by using my own…
Dakatine
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