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 ...

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50 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, ...
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1answer
39 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
105 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
289 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
55 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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2answers
65 views

limiting current from a photo diode to TIA [closed]

my simple configuration Photodiode current limits 10nA - 100mA Incident Light Characteristics: pulse width 10ns, repetetion rate 20us i want to protect the photo diode and the TIA input from ...
0
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0answers
26 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 ...
0
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1answer
47 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
47 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
59 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
79 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 ...
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1answer
16 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 ...
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4answers
115 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
28 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 ...
0
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0answers
69 views

Simple 1.2->12V, 5A current limiter circuit with limit indicator

I have a voltage source which varies between 1.2 and 12V, and I would like to limit the current between 1mA and 5A. The voltage source is a switch mode power supply, and the current limiter has to be ...
0
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2answers
49 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 ...
0
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4answers
151 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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0answers
110 views

Adjustable, Current Limit Regulated PSU (LM317)

I'm trying to build an adjustable, current limited PSU. The PSU will only need to source small currents (<150mA) at 12V. However, the current limit should be adjustable between 20-150mA. I ...
0
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1answer
63 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
80 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
votes
1answer
41 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 ...
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0answers
66 views

How to wire power transistor for increased load?

For just one LM317 Voltage Regulator this would work: With the emitter as VOUT. But right now I'm using two LM317, One for current limiting and the other one for voltage regulation, the circuit ...
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2answers
86 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\$ = ...
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0answers
10 views

Tradeoffs and solutions between low current transient responce and max. current in a lab power supply

Consider a CC/CV power supply implemented in a topology like the one in How to improve current control loop in power supply? Let's say it's designed for a high maximum current (like 5A) and includes ...
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2answers
75 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
40 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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1answer
39 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
66 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
95 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 ...
0
votes
1answer
87 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
84 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
votes
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
52 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
31 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 ...
0
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2answers
103 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 ...
1
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1answer
96 views

Need assistance in choosing diode for seat heater circuit

Background: I have been working on car seat heater circuit. I purchased the universal seat heater with manual 2 level (high and low) switch. Instead of manual switch, I re-wired the seat heater ...
3
votes
1answer
56 views

why Commutator power capacity is limited

A commutator's power capacity is said to be limited to a few megawatts. What are the reasons limiting it? I thought it could be like brush resistance and spark strength. What is the maximum voltage ...
0
votes
1answer
71 views

Voltages to keep my circuit running at 200mA with NMOSFETS

Im trying to build a circuit to send information using IR led, using pulse signals my leds (TSAL6400) operates at 1.35V, and their maximum pulse current is rated 200mA After struggling a bit with ...
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2answers
88 views

Why do we need to find the current?

I am beginner in electronics. What i came to know until now is that mostly we have to find the current in a circuit in our text books. I wonder what useful work we do after finding the current, dc ...
0
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4answers
162 views

How to increase the current in this circuit?

Im trying to build a circuit to send information using IR led, using pulse signals (Im trying to mimic a home appliance remote control). My leds (datasheet) operate at 1.3V, and their maximum pulse ...
1
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2answers
388 views

Smartest way to use current limit using LM317?

As i understand, using this circuit: Will cause the current to go right through the POT and resistor, which will generate a lot of heat. Is there a better way to use current limiting with LM317 ...
0
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1answer
54 views

Driving a 5V IR led with a 5V charger?

I'm trying to build a remote control with IR led. I'm experiencing low range with my 1.5V, If=50mA IR leds, so I looked for and found a 5V, If=100mA IR leds. twice the current, hence probably better ...
0
votes
2answers
80 views

Generic question about interfacing a microcontroller with a device: when is the current limit a problem?

I have an Arduino Board, to be precise many models, but let say I want to interface a ATmega328p with another integrated circuit (all is running at 3.3 V). In this case I want to connect Arduino with ...
0
votes
1answer
35 views

LTC1153 current trip off IC

I am using an LTC1153 IC, with an IRLML6346 MOSFET. I am supplying a 3.3V rail. Now, the output is being fed to an arduino board and the supply works. The Gate pin gives out about 7V (in conformance ...
2
votes
2answers
67 views

Where can I use my ammeter to measure the current set by the current limit potentiometer?

Here is the circuit in question: (http://i.imgur.com/Jmo6mzL.png) The circuit is an adjustable power supply that I have put together (can be bought here) and I am working on putting it all together ...
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2answers
116 views

How a sensor supply circuit should be? [closed]

i am looking for sensor supply circuit for a sensor. The sensor requires bipolar +-6V to -15V DC and 10 mA power consumption at 6V DC (6V*10mA=0.06mW). Also power supply of this sensor requires less ...
2
votes
1answer
71 views

adjustable IGBT current?

Goodmorning all, Here my very first question so I may be asking something that is may be already answerd but I couldn't find, My question is : How is current limiting achieved in modern IGBT based ...
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1answer
53 views

Adjust the power of laser diode on both CW and pulsed mode

I am working on my graduation project to build a laser unit, i am supposed to control the power of laser diode when operating in pulsed mode and continuous mode. firstly, i had the pulses from ...
0
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2answers
76 views

Help using transistor in active mode as a current limiter

Brief context: I have a small solar panel, nominal properties are 0.6W, 6V, 100mA. In given conditions I want to measure the maximum power it can produce - I do not want to do anything with this ...
0
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1answer
53 views

Using AC fuse for DC & DC fuse for AC…!

Recently I visited a site where I saw that in an inverter AC fuse are use for DC..it is quit odd for me..!!! Is it ok to use the same? What are the factors to be considered when we use AC fuse in DC ...