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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32 views

“General Purpose” Current Limiter?

So i have been trying for a few weeks to create a current limiter that fills my needs but i have failed/i don't even know if it's possible. Basically i want to make a current limiter that can work ...
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0answers
28 views

What are some good ways of creating a voltage adjusted foldback current limit?

I would like to add foldback current limiting to my bench power supply as a way to protect the DUT from too much current. I believe this will be helpful in certain situations, for example a DUT that ...
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1answer
42 views

Mini Workbench Adjustable Power Supply

I'm trying to design a mini workbench power supply to use for small electronics that is powered from the 12V rail of an old ATX power supply. I want it to be able to provide an adjustable voltage of ...
5
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1answer
79 views

Raspberry Pi Zero HDMI socket - available current?

I have an ongoing question on the Raspberry Pi SE site, in which I'm attempting to figure out how much current is available to devices connected to the HDMI socket of each Pi model. I think I've ...
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0answers
76 views

What's wrong with my SMPS circuit?

I've proto-typed a switch mode power supply with variable voltage and current control using a MAX1763 IC. I've powered it on and for the most part it works great, I can control the voltage using the ...
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3answers
46 views

What value PTC Thermistor should I choose for over-current protection for a child's electronics kit?

What is an appropriate value for a PTC thermistor used in a 3-cell AA battery pack to provide over-current protection if the terminalsare shorted? Current draw during normal operation will be only a ...
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1answer
50 views

Current and wattage overload

So, I have an extension cord reel with four outlets and current overload protection can handle a total of 2500W, 110V, 20A. Im confused about those specification because they do not add up but that's ...
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2answers
40 views

Limiting resistor for zener voltage regulator driven by transistor

I have this circuit: simulate this circuit – Schematic created using CircuitLab And I would like to understand why I need a limiting resistor for the current flowing through D1. I know ...
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1answer
126 views

Can two microcontroller output pins play tug of war?

Using an AtTiny85, I'd like to drive an AlfaZeta C30NR flip-disc component to indicate dead batteries for a small project. It is a semi-permanent electromechanical indicator that uses two pins, SET ...
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2answers
69 views

lm324 current can draw safely

as we all know lm 324 consist 4 op-amp now the datasheet says current limitation like 40mA. Now I want to ask that whether 40mA for each op-amp or the sum of all 4 op-amp Link to the datasheet here.
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36 views

How to distibute power between MOSFETs and resistors in current limiter cirquit

I thinking about making some sort of not-very-big-power hi-side current+voltage limiter, using cheap china SOT-23 P-chenel MOSFET like IRF9310PBF, BSC030P03NS3G or AO4407. But in some user cases ...
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1answer
78 views

Electrical power strips and current overloading

simulate this circuit – Schematic created using CircuitLab Currently there is an extension cord that runs from the wall with 10kA. The current on the cord says 10 amps, 125 volts, and 1250 ...
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1answer
105 views

How does this circuit do current limiting

Problem: my photo diode recieves pulses of width 10ns-150ns and repeating at rate of 1Hz-50KHz the current from photo diode depending on incident light can go from 10nA-100mA, so i have two photo ...
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2answers
104 views

LM358 Operational amplifier Ouput voltage rising with stable inputs

I'm modifying a step-up circuit based on UC3843 SMPS Controller to add a current limiting feedback to it. I'm using a low-side sense resistor (Rsense) amplified by an LM358: simulate this ...
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0answers
57 views

Limiting Output Voltage of the Opamp-to avoid saturation

Problem: my photo diode recieves pulses of width 10ns-150ns and repeating at rate of 1Hz-50KHz the current from photo diode depending on incident light can go from 10nA-100mA, in a nutshell, my ...
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1answer
136 views

Need some help about why this circuit (PSU) isn't working

Trying to make a current limiter for my LM317 power supply. This is the complete circuit: I found the current limiting circuit on the web, I'am powering this circuit from a 12V 20A switching lab ...
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5answers
387 views

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 ...
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1answer
99 views

current limiter for TIA, reducing the problem of distortion in over limit input

Problem: my photo diode recieves pulses of width 10ns-150ns and repeating at rate of 1Hz-50KHz the current from photo diode depending on incident light can go from 10nA-100mA, so i have two photo ...
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1answer
37 views

Is There a Symbol for an Inrush Current Limiter?

Is there a schematic symbol for an inrush current limiter, or is a resistor used instead?
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0answers
59 views

Transistor behavior in Current Limiting Circuit

I have a circuit that I think will work, but I am worried that if I am overlooking or misunderstanding something about transistors in current limiting applications. The following is nothing original. ...
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4answers
121 views

Simple soft start for high power mains device

I have seen, but cannot find again, a really simple implementation of a mains soft start circuit. The thing I'm thinking of involves a power resister inline of the mains. When the device is started, ...
0
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1answer
43 views

Quick question about the L200 circuit limit

I need some help on how to calculate the output current.. Datasheet: http://www.zen22142.zen.co.uk/Circuits/Power/l200.pdf I want to use the (Figure 2. Programmable Current Regulator.) But i don't ...
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4answers
113 views

Large parallel strings of LEDs

I want to drive multiple strings of XTE LEDs (total of ~36 LEDs). The relevent (-ish) specs are as follows: I_f,max = 1.5 A Desired I_f = 0.5 A V_f = 2.94 V (0.5A @ 85C) According to some ...
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3answers
311 views

Replacing zener diode with a resistor in current limiter circuit

Can we use a resistor to replace the zener diode in this current limiting circuit ? Why do you think using a simple resistance is not enough to trigger the base ?
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1answer
60 views

Negative voltage current limiting

I am trying to design a current limiter that limits current through R4 based on a typical transistor-MOSFET topology like the one in the picture: This circuit works fine. When the voltage accross ...
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0answers
27 views

Determine voltage limit from load capacitance limit?

I want to add a NTC thermistor (a.k.a. inrush current limiter, or ICL) to a circuit. But the manufacturer only specifies the following (and I'm giving sample values for the component I'm considering):...
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1answer
64 views

Current Limiting Resistors for Multi-Branch LED circuit

I have bought some of the following LEDs (going to try either for brightness/size): 100 Pcs 0603 SMD Superbright LED Yellow Light Emitting Diodes 40 Pcs SMD 1206 LED Lamp Yellow Light Emitting ...
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1answer
69 views

Active Current Limiter

I have a DC to DC converter that outputs 28v and charges a very large cap. (10mF). Cap acts as an energy source for a load that consumes lots of energy for a very short time. (A few amps for micro ...
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1answer
63 views

Safest way to limit current output of a signal generator

I need to feed a TTL-like signal (0-5V) from a signal generator to another equipment (herein 'load'), whose manual states that the input current should be about 10 mA, and 30 mA maximum. As I work ...
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3answers
90 views

How to prioritize a current path in a circuit [duplicate]

Here's my problem: I have a power supply rated at 5V, 2.1A I need this to feed two devices, both running at 5V Device one is a single-board computer that can consume anything between 0.5A and 1....
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1answer
18 views

Current rating of adapter [duplicate]

I have a 12v adapter which has a rating of 1.5A. 1.5A is a large current. I've used the adapter to power a microcontroller board. The microcontroller board has an lm317 linear voltage regulator to ...
4
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4answers
131 views

NPN vs PNP current limiter

So I'm trying to design two mirroring current limiters for a +-15 volt power supplies. I don't understand why these two circuits don't behave more like each other. The PNP circuit has +15 on ...
0
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1answer
34 views

Limit the current of a fixed voltage via MOSFET+PWM

I have a SMPS which I would like to current limit. The current limiter should have a negligible voltage drop when not limiting (say, <0.5%). I thought of inserting a MOSFET and a hall-effect ...
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2answers
50 views

Get practial resistances for the Current Divider [closed]

My understanding The resistance as seen through the load is just Rs, Therefore 60K < Rs < 80K. Is (current Through Rs Resistance) IL (current through RL ...
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5answers
236 views

How to limit current to LEDs

I have understood that this is a bad way to do it: Since some LED can draw more current than others. So lets say I would power some high powered LEDs, like say 10 x 3W LED with a DC forward ...
0
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1answer
81 views

FET Current limiter 30A and overload detection

I plan to make a module for my motorbike to replace fuse by current limiters and overload detection system. I've heard nice things to do with J-FET. It should work up to 12V 30AMP. The detection ...
3
votes
2answers
87 views

Likely consequences of slightly exceeding 500mA USB current

As we know, a USB 2.0 device, once it has properly negotiated with the host, is allowed to draw 500mA. Suppose that you are designing such a device, and your input current limiter chip is tuned by a ...
2
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1answer
54 views

Current limiting for at the input side of the transimpedance amplifier ( photodiode protection)

So I've used the standard trans-impedance amplifier to sense the current of a photodiode. The photodiode is unbiased. https://en.wikipedia.org/wiki/File:TIA_simple.svg#/media/File:TIA_simple.svg I ...
7
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2answers
94 views

How Do I Limit My Motor Current While Maintaining Voltage Drop Across It?

I am trying to build my knowledge of working with dc motors by using an IRF510 MOSFET to switch a motor on and off. Please refer to the schematic below to see how I hooked everything up. \$S_1\$ = ...
0
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2answers
78 views

What is the max current that this circuit can handle?

I'm making a simple project. For me, it is recommended that the output current is 1.5A. But it's OK if it is 1A or 0.5A. For voltage regulator: Datasheet says that the output current is up to 1.5 A. ...
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1answer
55 views

Cascading WS2803 LED drivers, each with different output current

I've decided on using WS2803 PWM constant current LED drivers. I'd like to cascade two of them and use the first one for 15mA output and the second one for 20mA output (each chip for driving different ...
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votes
1answer
40 views

Any suggestions on how to make a current limiting circuitry? [closed]

I am a student of Electrical Engineering and I am currently working on a biomedical device which stimulates a human arm through functional electrical stimulation technique. Now for instance, if short ...
0
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1answer
83 views

Control the base of a transistor (Current limit)

I looked at another question here and saw someone talking about different LM317 current limiting methods, and in one of the comments he uploaded this image: But no one answered the comment and I'm ...
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2answers
120 views

Current limit using MOSFET

I am driving a 24V DC Motor which can draw up to 30A and I would like to incorporate some over current/short circuit protection. As such I am planning to place a shunt resistor and power MOSFET(...
0
votes
1answer
105 views

Calculate Current Regulation - DRV8825

I am driving a bipolar hybrid stepper motor rated 1A with a DRV8825 at 12 V. About current regulation the datasheet says: 9.2.2.2 Current Regulation In a stepper motor, the set full-scale ...
1
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2answers
89 views

Is there a theoretical limit to power supply transformation efficiency?

As I'm looking at some resistive-load applications I'm wondering whether there are any rules that put an upper-limit on supply-matching efficiency. Because if a load isn't matched to the power supply ...
6
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2answers
1k views

Does skin effect appear in home wires?

A technician said: Its better to use a solid cables for homes (not stranded cables). I did not use any calculations but I think that stranded cables are better due to skin effect. We use 220V / 50Hz. ...
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2answers
55 views

How do I limit the current supplied to a DC motor?

I am designing a robot and my motors are taking up too much current when the robot runs into a wall or has the motors forcefully stopped. How do I limit the amount of current I give the motors?
0
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1answer
36 views

Limit current of L6206 bridge driver

I'm currently building my first stepper motor driver, a bipolar stepper, 4.5-48V 1A phase current with 4.5 Ohm phase resistance. I've built the circuit of the L6206 following the "Typical ...
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2answers
116 views

How does vacuum tube heating (heater voltage) affect tube performance/sound?

I have replaced a 12AX7 tube with ECC85 in my guitar amp. Seems to work great and sound great. The part that is questioning me is whether the sound is being at its best because it takes a good 20-30 ...