Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [current-limiting]

Current limiting is the practice in electrical or electronic circuits of imposing an upper limit on the current that may be delivered to a load with the purpose of protecting the circuit generating or transmitting the current from harmful effects due to a short-circuit or similar problem in the load.

Current limiting is the practice in electrical or electronic circuits of imposing an upper limit on the current that may be delivered to a load with the purpose of protecting the circuit generating or transmitting the current from harmful effects due to a short-circuit or similar problem in the load.

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Correct formula for LED current-limiting resistor?

I'm trying to work out what value resistor to use in a LED circuit. The equation I'd use to do this is: $$ R = \frac{V_{cc} - V_f}{I_f} $$ Seems logical, and makes complete sense. The answers to the question How do I calculate the resistor value for…
Jeremy Kerr
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Solution for adapting to USB current draw limits?

Summary: I'm setting up a USB-powered Li-ion charging circuit and would of course like to draw the maximum charge current possible situationally -- but also want to ensure I don't violate the USB specification on current draw. While I have been able…
boardbite
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Are there still practical modern uses for large through-hole resistors?

When teaching electronics to college students, we often use these large 1 W cylindrical resistors - not because we need the wattage rating, but because they are easy to handle and read the color code for students. This got me thinking: almost all…
user1247
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Does an over voltage, over current and reverse polarity protection IC exist?

I'm designing a circuit that has the following protection requirements: Reverse polarity Over voltage (60v max) Over current (approx 1A) There's quite a large input voltage range, 10v to 60v. 48v is nominal, drawing about 150mA. At 10vin, it draws…
raaymaan
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P-Channel MOSFET Inrush Current Limiting

I have been searching EESE and Google for several weeks now for a solution to this problem, and while I found some proposals that seemed promising, the real-world implementation fell short of expectations. I have a voltage regulator on a board with…
DerStrom8
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Why does this optocoupler's datasheet recommend splitting a current limiting resistor in two?

And not only that, they also want to keep a ratio of R1/R2=1.5 The opto in question is ACPL-M21L by Broadcom Here's a link to the datasheet: https://docs.broadcom.com/docs/AV02-3462EN Thanks.
mbmsv
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Prevent overcurrent while filter capacitor is charged

I have this circuit: On start-up, the power supply experiences an overcurrent condition, because when the capacitor is charged, it looks like a short circuit as seen from the power supply. How can I prevent this? Adding a current-limiting resistor…
user54579
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Why is LED lighting up despite Supply voltage < Forward voltage

I have an LED which has specified Typical forward voltage of 3.5V and Maximum forward voltage 3.9V. I applied 3.3V across it with a 300 Ohm resistor in series. Why did it light up? I am wondering if I can pick this LED as a reliable choice for my…
boardbite
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Does oxidized copper conduct electricity?

When the surface of copper turns that greenish oxidized color, does the resistance to current flow increase or isn't affected? For instance if the point of contact is secure and clean but bare visible copper wire has oxidized will it still conduct…
ohmmy
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current limiting a shorted load to 20A

Analog newbie here and first time on this forum... thank you for reading! What I have is a control for pyrotechnics. I have all the digital control stuff figured out, but analog bits are not my forte. Car battery supplies this rig, and output…
shorted.neuron
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Which reverse polarity protection is better and why?

You can find two such circuits using a diode that protects against reverse polarity, i.e. against wrong power connection. I wonder what is the point of using the D2 diode, since the current flowing through it will damage it - at least that's what…
Jerzy Przezdziecki
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What is high side current limiting?

What is high side current limiting? While google searching for the term I have found ICs that describe their application as "high side load switching". Is this the same thing or something utterly different? Furthermore, the term implies that there…
learnvst
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Multiplexing UART

I'd like to interface my main microcontroller's hardware serial port to more than one device at the same time. My understanding is that UART on my microcontrollers is based on an active-low 5V TTL. (I know what I'm explaining here can be technically…
David Refoua
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Simplest, cheapest, fast and minimum footprint current limiting circuit with low resistance in normal state

I have a digital output, driven by the high-side driver with nominal voltage of 24V DC. The load current normally is below 100 mA. The output is monitored, so I can switch it off quickly if I detect a short circuit at the load side. The problem is…
syoma
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Limiting current WITHOUT dropping voltage

I'm trying to limit a current of a 5V power supply to 100uA. I was first thinking of putting a 50k resistor. That will never allow above the treshold. However, the load requires at leas 4.5V and varies in the amount of current in needs. So this is…
TheMeaningfulEngineer
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