Questions tagged [current]
Flow of electric charge - typically movement of charge carriers, such as electrons. Measured in amperes (A).
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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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Confusion about relationship between energy per coulomb, and the amount of coulombs in current
I am trying to understand how a power supply works and working from the ground up I am learning about electricity, voltage, current, amps, and wattage. I am new to this stuff so I apologize if this is ...
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Is a node always considered to be 0 volt when it's connected to a ground?
Can we directly say that a voltage at a node (voltage at point A) that shares a ground is always equal to 0 Volt? (I'm assuming right-side of the point A doesn't affect the solution as long as the ...
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DC motor, confusion in specification about Current
So, I am trying to build a little robot mower, and getting all parts. So I recently buyed two DC 12V motors, here is the specs:
Now I am trying to calculate how big or which battery should I use, and ...
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3.3V to 5V logic level shifter with 3.3V microcontroler board and 5V arduino sensor
I would like to use logic level shifter like the one above.
3.3V logic level would be connected on NodeMcu 3.3V microcontroller board pin, while 5V level would be used for Arduino sensor.
What ...
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How to find out how much voltage and current a soldering agent can handle
Is there any way to find out the maximum voltage and current that a soldering agent can handle based on the material and/or the information that I find on the package?
For example, I have this ...
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Why the current equation is different in BJT application?
This is the link I am refereeing for the my study. I am trying to learn how the diode current equation is applied in BJT for differential and common mode analysis. This is the current equation from ...
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Relay continuous current ratings vs size
I am designing a relay board for my motorcycle to control power to various accessories - lights, heated gear, horn, GPS, etc. It's a pretty straightforward design, some terminals, fuses, and relays.
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Low current cut off
As you know, with solar panels, current lags voltage by a lot.
I want to run a DC pump straight from a solar panel. Simple, easy to maintain, low cost setup (relay, SS relay, diodes, etc.)
In the ...
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What is the power requirement for switching this relay?
I bought a heavy duty relay to control fluid pumps. I'll have a 12VDC power source to operate the pumps and I bought the following relay board to control them using an Arduino or other type of board.
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Limiting the current powering a circuit
I have an LED bar that draws about 1.17A when connected to a 5V 1A external USB battery. The voltage across the terminals measures 4.61V.
The LED bar draws about 1.7A when connected to a 5V 2A ...
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Energy meter neutral current measurement
I was reviewing an energy meter specification and I came across neutral current measurement.
What is the importance of neutral current measurement in an energy meter for three phase power supply?
I ...
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Reverse voltage protection circuit operation
I have this reverse voltage protection circuit:
Can someone tell me how this circuit protects from very high reverse voltages? I am not able to understand how the capacitor is connected in such a ...
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How to calculate how long a 9V battery will last based on schematic?
So I made this schematic for a little bathroom light I made. I would like to figure out how to calculate how long the 9V battery I connected will last with this specific schematic. The diodes are LEDs....
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High current problem
I have this circuit:
I was asked to measure the inrush current for this circuit section.
One floating output actually goes to a microcontroller input and the other goes to an op-amp input terminal. ...
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Working of the "Capacitor Reset" block
I am reading this App Note. On page 6, Figure 5, they have provided a circuit which helps with the soft start and input protection circuitry.
I am not able to understand the "Capacitor Reset&...
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Buck converter current
I have this synchronous buck converter.
Input voltage - 8.7V
Output voltage - 5V
Switching frequency - 350kHz to 450kHz
Output load current is 2A
Schematic:
I have an input capacitor of 68uF and an ...
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Best way to run current for certain amount of time
I have a circuit set up that requires around 5 Amps of current to run but I need it to only run for a specific amount of time. The circuit is activated when I press a button and I want some tool to ...
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Using High side current sensor as a low side current sensor
I have a very small question to ask. Is it ok if a high side current sensor such as the MAX9929 be used as a low-side current sensor as well? Or should I look for some parameter in the datasheet. The ...
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Pls help by answering.Thank you.Need to understand before proceeding further [duplicate]
I have some doubts and confusion. Please clarify by explaining the science behind it. Thank you. I have no knowledge in electicity. Regardless what i put as voltage and current is just example, just ...
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When and how does a buck converter behave in a boost converter mode?
My question is with reference to this answer for this previous question.
The answer states that a buck converter will behave in a boost mode for some cycles during light load or no load condition.
Can ...
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Can I connect a mobile charger of output 5v 2amps to power a 3-6v dc mini motor pump of current intake 130-220mA? [duplicate]
I wanted to power a 3-6v dc mini motor pump using mobile charger do I need to use a limiter to control the current since motor requires only 130-220mA and charger output is 2A
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I get different results whenever I try to solve this circuit problem with superposition theorem. Can you please help?
My recent results are like this:
i= 11,174
the current exiting from Vg= 3,304
V=53,1
I am doing something very wrong but I can't see it. My values even don't correct each other. Another thing is if I ...
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Can you explain this solution to find Isource (Thevenin Norton)
I know it is current division method but how is it applied ?
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How do i measure current in 10uA till 10A range in steps of 10uA?
I'm planning to build a circuit that measures the current from uA till 10A DC Line. Initially I thought of using HECT, but it is having better accuracy in higher current range. so I'm figuring out if ...
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Determine resistor power rating using data sheet?
Info:
I am having trouble properly calculating the power rating for a resistor on a robotics design.
I have a circuit diagram which I need to use for my power calculations.
Can someone please clarify ...
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Amplifier Current Noise Imaginary Impedance
Does the current noise spec of an amplifier need to be multiplied by only the real R component of impedance on it's input or the total impedance? Would increasingly larger inline capacitor values ...
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Starting torque of series vs shunt DC motors
Recently, I read that starting torque of series motors are much higher than shunt motors.
I try to find out what is reason behind it and I get to know that this is because in DC series motor torque is ...
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How do I safely power 2 m 144 LEDs/m WS2812B strip with 5 V and 10 A?
I am using a 2 meter strip with 144 LEDs/m on a WS2812B LED strip. By doing the maths on how much current would be required to power this we get:
60 mA * 288 = 17.28 A.
However, I am not planning on ...
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Overcurrent protection, limit for nominal current or stall?
Background: I'm currently working on a robotics design that will drill through soil.
I have selected a 48V motor who's nominal current is 3.17A and has a stall current of 42A. I will be driving the ...
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Derivation of Discharging Current of an Inductor
Consider the following circuit:
When \$t > 0\$, the inductor \$L\$ begins to discharge. I already know from KVL that the sum of voltage drops in the loop containing the inductor is:
\$L\frac{di(t)}...
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Id, Vds calculation
Simple and strange, looking at datasheet of BSS138 (Graphs) for this circuit below which is always ON Saturation mode Mosfet, Rds-ON = 3.5 Ω, VDS-ON = 0.1 V to 0.2 V.
Id should be 16.66 mA but ...
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Op-Amp dynamic hysteresis
What is dynamic hysteresis in Op-Amp?
I read section 4.3 of the this App Note and was not clear.
Can someone explain me why this is happening?
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How is a differentiator op-amp current possible?
I have been reading about op amps and came across this description of a differentiator variant using a capacitor.
The author explains that current can go through the capacitor when there is changing ...
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Measured voltage and current different from the calculated value
I am learning a simple LED and resistor circuit. I have the following components:
One 5mm blue LED
5V USB power source
From what I've learned so far, I am using the following forward voltage 3V and ...
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Current adjustment circuit seems to skip resistors?
I have the following current adjustment circuit, VDC is 32V. I want to be able to switch between two COB LEDs and adjust the current however the current should be much lower than it is in practice (it'...
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Voltage Divider to Power LED
I want to construct a voltage divider according to this schematic. I want to set the R1, R2, and R3 voltages to power a LED with a forward voltage of 3,5V and a forward current of 25mA. How should I ...
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What happens when the direction of initial current through an inductor is opposite of the direction of applied current?
I am having trouble understanding the behavior of current through an inductor when the direction of applied current is the opposite of what is initially flowing through it. An example is that when an ...
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How to determine max amps over a common ground between AC-to-DC Adapters?
How can I determine the expected and max current running over a common ground wire between DC of AC/DC converters? Should I fuse the wire?
I have two 5V/40A AC-to-DC adapters (AC is 3-pin each) for x-...
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Is it safe to use a 27A battery instead of a 23A battery in my doorbell? [duplicate]
I have a device that says it takes a "23A 12V" battery. I ordered a new battery and was mistakenly sent a "27A 12V" battery; same voltage, higher current. Is it safe to use this ...
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Why can we measure current in AC voltages?
From Wikipedia:
The drift velocity deals with the average velocity of a particle, such as an electron, due to an electric field. In general, an electron will propagate randomly in a conductor at the ...
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Transistor is OFF but the voltage at the emitter is the same as voltage at the collector
This is simple simulation below of an NPN transistor:
In the above transistor, without giving any base voltage, whatever voltage I give at the collector of the transistor, I am getting at the emitter....
user220456
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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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Joining nichrome wire within 1140 celsius kiln
I am trying to join 2.5mm diameter nichrome wire in my wife’s pottery kiln (1200 degrees celsius.)
I can’t find nichrome inline crimps, copper crimps won’t last. I am resorting to a steel bolt ...
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Heat of 12 LED lights 60mA 3.6W PCB
I’ve designed a PCB that is 50mm by 48mm
It’s a simple 12 LED light board, each LED has its own 36 ohm resistor and is all powered by a 5V supply
each LED runs off 60mA and uses 0.306W
The resistors ...
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What part do I need to increase current output
I am working on a mobile robotics personal project with a Raspberry Pi 3 Model B. The 4.5 VDC motor controllers on the rover has a no load current of 190 mA and a max load current of 250 mA. (I am ...
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What kind of current division is this [duplicate]
Can you explain why it is 6 * (3/9) ,Why don't we add 5kΩ resistance too,
How is this a current division,what is the formula for this.Thanks..
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Voltage drop through a resistor for a single charge, contrasted to a non-ohmic component
Recently I have been reading about how transistors and diodes only drop a limited amount of voltage across their leads for a wide range of currents. So the voltage drop per charge (at a given ...
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Determining line-to-line vs line-to-neutral loads in split-phase panel
I have a split-phase sub-panel, with two 120V legs (red/black) and middle neutral (white). Given Hall-effect current sensor clamps around some combination of red/black/white going into the sub-panel, ...
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How can this current division happen?
As far as I know, current division for spesific place's formula is:
Ix=(Req/Rx)*Isource However, here,the solution is 3/(3+2+4)*6. How is this a current division ? Can you explain this to me
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