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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4
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3answers
86 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
votes
1answer
25 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
votes
0answers
53 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
votes
2answers
48 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
votes
4answers
144 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
votes
0answers
66 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
votes
1answer
54 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
75 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
38 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 ...
0
votes
0answers
63 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 ...
7
votes
2answers
81 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
votes
0answers
9 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 ...
0
votes
2answers
72 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. ...
0
votes
1answer
34 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 ...
-5
votes
1answer
37 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
votes
1answer
57 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 ...
1
vote
2answers
83 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
74 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
vote
2answers
81 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. ...
0
votes
2answers
49 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
votes
1answer
29 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
votes
2answers
90 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
vote
1answer
88 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
55 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
70 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 ...
-1
votes
2answers
85 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
votes
4answers
151 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
vote
2answers
331 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
votes
1answer
49 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
74 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
61 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 ...
0
votes
2answers
112 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
67 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 ...
-1
votes
1answer
41 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
votes
2answers
70 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
votes
1answer
51 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 ...
0
votes
0answers
105 views

current sense circuit - High side sensing/Low side sensing

I want to measure the current through the 2 ohm Load resistor.I have read about high side and low side sensing.But I am confused about which method should I use in my case as the FETs are part of ...
0
votes
1answer
68 views

3V Current source with low voltage drop

I'm trying to make a IR laser diode driver which needs 1.9V and ~80-100 mA constant current. Most of laser driver circuits in web has LM317 as a current source but that design has always voltage drop ...
0
votes
2answers
59 views

Given Vf across a LED, what is the current draw?

I have sourced some LEDs from everyone's favorite high-quality electronics marketplace, eBay. I have a simplistic "datasheet" for the 7-segment LEDs that I purchased, which show a Vf of 3.8v across ...
0
votes
0answers
58 views

Question about Power MOSFET current limting

I am studying current limiting technique for Power MOSFET(P-ch). The material is AN1542(Active Inrush Current Limiting Using MOSFET) ...
2
votes
1answer
67 views

480 VDC Series Battery Bank - Solar PV Charging Current Feedback Control Circuit

I have a 480VDC Lead Acid Battery Bank (40 x 12VDC 50Ahr Batteries in Series) directly coupled to a 5.0 Kilowatt Solar PV Array [with an output range of 560-580 VDC and maximum output of 8.9 Amps). ...
0
votes
2answers
139 views

Current limiting with MOSFET

i want to limit the current through a MOSFET (high side) as simple as possible. The MOSFET will switch 600V and approx. 150mA for 1-2 seconds. The focus really lies on simplicity. I know that i can ...
2
votes
2answers
111 views

Is a resistor needed between logical pin and base/gate transistor?

I'm using a logical pin output (3.3V) to drive a NPN darlington transitor with the max current possible to minimize the fall and rise times. My microcontroler has a 20mA max output current per logical ...
2
votes
3answers
84 views

Need assistance with current limiting resistor for LED

I am seeking some advise on a making an infrared light source. I am using IR LED SE-5455-2. I have found some calculators on line but the results vary. I have also read many threads here. I am ...
3
votes
1answer
145 views

Detecting a coil is fully energized

I'm working on customized ignition system and want to implement the final stage as robust as possible. The ECU (Engine Control Unit) provides TTL level control signal to drive ignition system. The ...
0
votes
2answers
116 views

If I drive an LED whose forward voltage is 2V with a source that's 3.3V limited to 20ma, will I harm the LED?

Background: I built a 10x20 LED matrix for use inside a jack-o-lantern. The matrix is driven by 74HC595 shift registers that are connected to an Arduino. I've attached the Vcc of the shift registers ...
4
votes
2answers
120 views

Why sample current via lopsided resistive divider?

I'm studying the constant-current circuit of the Agilent E3610A 15V 30W DC Bench Power Supply. The entire schematic is at the end of the user manual, but I've redrawn the parts of interest here for ...
0
votes
4answers
96 views

How much hold current is consumed when there is no load?

Given a 24V 1A motor with no actual load connected (just a piece of orange tape so we can see the shaft moving). How much current will the motor use if I configure the driver board for 2A maximum ...