Flow of electric charge - typically movement of charge carriers, such as electrons. Measured in amperes (A).
current is the flow of electric charge - typically movement of charge carriers, such as electrons, and is measured in amperes (A).
Questions tagged [current]
6705 questions
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What causes a fuse to blow, the current or the power?
Fuses and circuit breakers are often specified at a certain current they will 'blow'. Increasing the current will also increase the power. So if a fuse is rated for 12V DC and 20 A, this would be equal to 240 watts. If a different voltage is…
Jackson Harvey
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Why is there a small cut in this ampere meter shunt?
I have seen lots of ampere meter shunts like this. What is the reason for this small cut?
user_fs10
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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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Two black boxes display the same impedance at all frequencies. Which has the single resistor?
Two black boxes display the same impedance at all frequencies. The first contains a single 1 Ohm resistor. Each end is connected to a wire, so that two wires protrude from the box. The second box looks identical from the outside, but inside there…
Paskualino
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Whats inside a resistor?
How does a resistor "resist" current/potential? I know it's an elementary question, but I'm sure others are wondering too.
Shubham
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"Ground" vs. "Earth" vs. common vs. negative terminal
This may just be me not having a degree in electrical engineering or electronics, but the whole notion of "ground" and "earth", when used in electrical circuit diagrams (especially integrated circuits), is extremely confusing. I guess the whole…
jrista
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Current flow in batteries?
I am reading a basic electronics book: "There are no Electrons: Electronics for Earthlings" and I came across a clever passage about the fact that you need a closed circuit in order for current to flow. Here is the passage I am curious about: "This…
mike
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Why is earth used for ground? Literally earth?
I never considered earth to be particularly conductive. It's just dirt, after all. However, I've seen "earth ground" conductive stakes driven into the ground in order for electricity to be grounded, because it will find its way down there. However,…
user3916009
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Does MOSFET let current flow through source to drain as it allows it from drain to source?
Does a MOSFET allow current flow in reverse direction (i.e.; from source to drain)? I made a Google search, but couldn't find a clear statement about this matter. I have found this similar question , but it is about detecting current direction from…
hkBattousai
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Why is it bad to mix new and old batteries?
I've seen warnings that it's bad to mix new and old batteries -- why? Is it a matter of a battery's age or a battery's voltage/current (remaining)?
Coldblackice
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Parallel MOSFETs
When I went to school we had some basic circuit design and stuff like that. I learned that this was a bad idea: simulate this circuit – Schematic created using CircuitLab Since the current will almost certainly not flow equally over these three…
BufferOverflow
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High PCB copper thickness: What are the pitfalls?
We need to carry high currents on a PCB (~30Amps sustained), so we are likely to order our PCBs with high copper thickness. So far we've only used 35 microns (1 oz) in our designs, so 'high thickness' for us means, 70 (2 oz) or 105 (3 oz). We do not…
SomethingBetter
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How much current can Solderless Breadboards handle?
I'm working on a project with a few stepper motors. I want to breadboard them so I know the circuit works well before creating a physical PCB. Each of the three motors is rated 2A, but I'll be prototyping with 1A (controled with driver chip) at 12V.…
Anonymous Penguin
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Do electrons actually flow when a voltage is applied?
It's said in books that a circuit is a closed path and thus that electrons come back to the source. If that's the case, what would happen when there were an earth fault in a circuit? How would the electrons return to their source? Do the electrons…
Ranjit
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How to carry high current on PCB
I need to pass high current on some part of my circuit. I used an online PCB track width calculator to see that required track width is about 5mm and minimum clearance is 1mm, which makes it about 7mm width at total just for one track. I need…
hkBattousai
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