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.

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What type of motor is this, and how could the power be limited? [migrated]

I've got a aircondition unit (Wood's Cortina Silent 12K Wifi) that is way to powerful for the intended room. I'm hoping to limit the effect to 75-50% to reduce noise, but I have no idea how this ...
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Need to limit the torque on a spooler

I'm a newbie to DC motors. I'm trying to use a geared DC motor of 150RPM 70Ncm torque to pull in rope on a small spool. The rope is being released by other equipment. This rope is being released at ...
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Do I need a current limiting resistor with an industrial rail DIN optocoupler?

I'm going to use this industrial opto-coupler: Optocoupleur RS PRO, montage Rail DIN, 6 mA In its specs document they don't mention the need of a current limiting resistor. I always add a current ...
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What's the difference between Maximum working current and upper limit of instantaneous current? [closed]

I am seeking to protect a Mabuchi RS-380-SH4535 motor + battery system using a BMS. The battery is a single cell 18650 LiIon. The motor has a stall current of 15 A at maximum battery voltage. My ...
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3 votes
2 answers
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How to design an adjustable 5A current regulator with LM338?

I have recently taken interest in laser diodes, and I would like to drive one of them (NUBM08) without destroying it. Looking over the internet I learned there are many devices one can build to do ...
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FoldBack Desing [duplicate]

I'm having a problem designing a foldback. I need it to have an opamp and a transistor. The problem is that the models I've been looking at don't work. I have to fulfill that for Imax=1.5 amp, go to 0....
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How to determine maximum continuous current on a DC motor?

Is there a good way to determine the maximum continous current a small DC motor can handle without breakdown? I am working with a high school robotics team. They are using a door lock actuator to ...
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Should I be concerned with the higher current draw coming from a part of my circuit design, and if so, how should I limit it in my circumstance?

I'm designing a voltage controlled oscillator for a modular synthesizer. My planned range for this circuit is anywhere between 37Hz to ~20kHz. Here's a schematic of it I made with the Falstad ...
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2 votes
1 answer
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LM317 current limiting/set via differential amplifier works in simulator but glitchy when built

I am trying to build a single LM317 power supply, with current limiting using a differential opamp and potentiometers. I've came up with this (see schematic) and have built it on a breadboard but the ...
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protect from in rush current of buck convertor

I made a PCB base on the following schematic, it uses a buck convertor for 12 to 5 v and then uses an LDO for 5 to 3.3 to run my ESP module I use 2 P-channel MOSFET for polarity protection , but ...
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Split current in a circuit?

I am looking to power an Arduino from a 12 V, 5 Ah lead acid battery, hooked up to a solar charge controller. (Max output: 12 V, 20 amps). I am also looking to power a Peltier Device, in order to cool ...
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How to limit power to LED, efficiently

I am looking to use a 12V, 5 ampere car battery on a small 5V, 2A LED. Typical applications online use a resistor or voltage regulator, but since I am using a battery I would like to conserve power, ...
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Using resistor with 110 V LED indicator to make current measurement between 50 - 70 mA

I need your guidance with the V=IR formula. It's probably a simple question but I don't have an electrical background. I am working on making an LED simulator panel for railway signaling interlocking ...
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How can I limit input current to a raspberry Pi to 2 amps from a high current battery?

The circuit I currently have consists of a motor circuit and a raspberry pi circuit connected to the same battery. (2 series circuits from the same battery). The problem is that during idle motor, a ...
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current limiter with MOSFET

I got a circuit from a current limiter for 12V by using a P-MOS, this is apply at the output from a DC/DC converter, I have to limit the current for 5 different voltages. I want to understand how the ...
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How to create current limiter to limit phone charging current to 500mA?

I have this neat iPhone case from AudioMod (https://www.audiomod.com/audiomod) that has a built-in headphone jack. I'm looking to upgrade from my 6S to the latest iPhone SE, which is the iPhone 8 ...
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LED Matrix to reduce current consumption

I'm trying to control RGB LEDs via USB. All LEDs have the same color, so I'm controlling them with only 3 PWM signals (generated from a PIC). The problem I'm facing is to reduce the current needed in ...
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PNP Darlington pair as a current limiter

I am trying to analyse what is controlling the load current in the below Darlington configuration. Is it the base current of transistor Q3 which is controlling current through R14 / emitter current ...
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If I just keep decreasing the resistance of the wire between the load and the battery, does that mean that the current flow is increased?

If I keep decreasing the resistance of the wire connecting the load and the battery, will the current flow increase, until the maximum current level the specific battery can give is reached? If so, ...
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How do I increase the current a battery delivers? [closed]

Let's say there's a 2Ah battery with a C rating of 2C. So this means that I could discharge 4 amperes for half an hour at best. Now, there is a default current that we get from a battery right? How ...
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Spark generator current limiter

I am using a spark generator for electrical discharge machining and mounted a current transducer to read the current value of the arc between workpiece and electrode. When the electrode gets too near ...
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Creating a simple address and data bus with Arduino Uno as a master using 3-state buffers and decoders

First of all, sorry if my post is too general. If you know a better place for this post please let me know. Problem I have 5 motors to be controlled independently (but not simultaneously, i.e. one ...
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SPI connection to Raspberry Pi

I want to flash and configure a processor using a Raspberry Pi. For this I'm using the SPI pins of the Raspberry Pi. I read that the Raspberry Pi pins can provide no more than 8 mA out of each pin. Do ...
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LM358P doesnt respond to inputs

I am currently building a Li-ion cell capacity tester. The circuit has two parts, one that charges the cell, and one that discharges it, but I have removed the charging components to make the circuit ...
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Powering Multiple Raspberry Pi circuits via GPIO header power pins

Goal: I wish to power 3 Raspi. I am currently running 3 USB C wires powering the device, but I wish to build or find ways to power them all using GPIO header power pins. Background: Mechanical ...
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Led strip and relay current splitting?

I have a 12 V LED strip that works at 10 W. I want it to run at multiple current configurations with two relays and without the help of a microcontroller. I am attaching a diagram of my intended setup....
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Current limit to 500mA (maximum) at 12V

I have a 12V DC output which can output 1A (maximum.) I want a circuit that limits the current to maximum 500mA, so I don't accidentally draw more than 500mA as that would probably mean I have shorted ...
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Can we add a current limiter circuit to LM2576 fixed voltage version?

I know I can add an external current sense and comparator circuit to the feedback pin of LM2576-ADJ version to limit current, but can we make such a modified arrangement to a fixed version of the ...
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Simplest current limiting method for battery charging

I need to charge 12V car battery (from main battery), but I have to limit current, because power cables are quite thin and I don't want to draw too much power from main system (in case battery is ...
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How to spread a current spike?

👋 I have a 12V circuit powered by a 'smart' power supply feeding two USB sockets (similar to this one). The two sockets are parallel to each other and in series with a simple switch. Whenever I ...
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Why would you place a resistor in series before AND after a diode (see simple circuit)?

For an assignment we had to first simulate a circuit (first with a Schottky then with a rectifying diode) in LTSpice and then do measurements on an actual circuit before answering a few questions. ...
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How to switch between solar panel and battery in order to power supply load

I'm doing a charger from a solar panel for a Cubesat project for my university. I made the buck converter from a 20 V solar panel in order to charge the battery. This works well with Arduino, where I ...
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Why do stepper motors draw less current at higher speeds?

I have an A4988 and a NEMA17, when I set the current limit to 1.5 A and the motor runs at a low speed of 0.2 RPS I measure the current and effectively it draws 1.5 A. Now when I run the motor with the ...
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DC motor with torque control

In general I would like to make a circuit, where I have: a power supply (batteries), a dc motor, a button (when holding - close circuit, otherwise open) and maybe a power switch, just in case. I would ...
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NTC for inrush for DC/DC with DC input voltage

I want to limit the current to my DC/DC input. At first, I wanted to use a resistor, however, I also came across an NTC for inrush limiting. So I basically want to change R1 with an NTC. The specs for ...
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Do you need a current limiting resistor on an enable pin?

I am using MCP16312-E/MS buck regulator and need the component to always be on. I am therefore connecting the enable pin to the Vin supply. Do you need a current limiting resistor? Whilst the resistor ...
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PTC Resettable fuse

I need to limit the current of a motor to around 1A. I would like to use a PTC fuse so that it trips in the rare occasion the motor is forced by the user to draw too much current because the motor is ...
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Voltage (or power)-current relation of a small supercapacitor

Is size a factor that limits the maximal current that a capacitor can take? I got this question when seeing Figure 7 of this supplementary material of the research of the smallest super-capacitor now. ...
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What happens when you reverse bias a NMOS with separate body terminal?

I am trying to create a current limiting circuit with minimal output capacitance. I'm trying to build a circuit that optimises low parasitic output capacitance over linearity. I used a SST215 DMOS ...
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Calculate the correct current limit for driver A4988

Im using the driver A4988 together with stepper 28byj-48. Ive read somewhere that the correct current limit on 28byj-48 is somewhere between 0.1-0.15 v. However if I feed it with 12 v there is a high ...
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How does an inverter control current?

I understand how to control voltage. If I have a buck converter supplied with DC voltage (\$V_{DC}\$), I can command the output voltage (\$V_{out}\$) directly via the duty ratio (\$D = V_{out}/V_{DC}\$...
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Voltage output on current regulator drops when I power ammeter via same power supply as circuit

I am running this cheap ammeter on a NPN transistor based current limiter. When I attempt to power the ammeter via the same power supply as the current limiter, the voltage across the current limiter ...
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3 Phase breaker - Current Limit

I have a simple question... If I have this 3 Phase breaker: That means its current limit is 20A right? My question is, is it limit for the whole breaker or limit for every phase separately?... What ...
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TPS24701 Overcurrent Protection Blowing the MOSFET

I'm trying to create a circuit that will cut out if >5A is drawn downstream, using the TPS24701 hot-swap controller. It looks designed for exactly this sort of thing. Here's my cicrcuit: I clearly ...
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How to limit the current in a circuit in a DC-DC voltage buck converter

This is something I've been stuck on for quite awhile, so I wonder if I'm overlooking something. This is what I have: I have built a simple DC-DC buck converter that should be operated with an Arduino ...
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-1 votes
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How to set loading(resistance) when i try to simulation Darlington pair limit current between Voltage 9 to 36

How do I set my loading (R13) value for simulating Darlington limit current between 9 to 36 V? If there is no loading (R13), the result of Q1 current (C to E) would not show correctly, but a placing ...
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How to power (from AC) & set varying overcurrent limits on the fly for 12 V DC motor

I am trying to use a 12 V geared down (high torque, low speed) motor in an exercise application. I want to be able to roughly adjust the load akin to adding more physical weights on a traditional ...
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Sizing series resistors for logic inputs of a BLDC driver

I'm designing a BLDC motor driver using the MP6532 driver. Pg. 4 of the datasheet specifies the Logic Input Current as +/- 20uA. ...
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Switch-on time of an active p-channel MOSFET current limiting circuit

I have recently posted a question on the design of an inrush-current limiting circuit: Current limiting circuit with P-Channel MOSFET I have decided to post a new question on how to analytically ...
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Fixed current limit

I am going through The Art of Electronics, 3rd Edition improved. In chapter 12.4.4, Protecting power switches, Figure 12.45 shows current limiting the high side switch; B: fixed current limit: ...
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