Flow of electric charge - typically movement of charge carriers, such as electrons. Measured in amperes (A).

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9 views

Max current prior to fuse?

I have a 2 meter long wire, that is 1 mm in diameter and it's resistance is 0.042Ohms. I plan to have 100A of current flowing via that wire for 90ms. Could it handle that large amount of current? If ...
0
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0answers
43 views

Series/Parallel configuration?

If I had a large bus bar, then split it into to pieces, and in between I connected them via separate wires that have their own insulation depicted in this simple diagram: At point A it shows the ...
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0answers
42 views

What is the best way to configure an electric fireworks igniter

I've seen a bunch of tutorials on creating a fireworks igniter using, a resistor or a piece of copper wire and a 9 - 12 v battery. Basically you the resistance from the small piece of copper or 1 ohm ...
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0answers
40 views

Can I use General Purpose Printed Circuit Board for any voltage or current rating?

The thickness and width of the copper pad (1 ounce/ 2 ounce) depends on the current that will pass through it. Can the General Purpose PCB withstand high currents (up to 15/20A)? If not, is there ...
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3answers
40 views

4-20mA Loop powered DAC

I was selecting a DAC for HART network and in the process I came across two terminology. 12-/16-Bit, Serial Input, 4 mA to 20 mA, Current Source DAC AD5420 and 16-Bit, Serial Input,Loop-Powered, 4 ...
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2answers
42 views

How to calibrate an ammeter and voltmeter?

How can I calibrate an ammeter and a voltmeter. I just want to know about it. Because it might be helpful and I think it is a vital thing to know. So how can I do this?
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1answer
42 views

Is there a way to calculate the proper wire gauge?

I'm looking for the right copper wire gauge for my project. I've found several charts listing the maximum current that various gauges, solid and stranded, can transmit. The charts often disagree. ...
1
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0answers
16 views

Laser diode driver at high currents

I have a fiber array package laser diode which draws 30A at 2.8V. I would like to use it in a laser cutter project, but I don't know how to go about designing a power supply for it. I came up with ...
2
votes
1answer
66 views

Understanding a current sensor circuit

I'm struggling to see how the output of this circuit is $$V_{0} = {I_{s} R_{s} R_{L}/{5k}} $$ My work thus far: I understand the voltage into the base of the BJT is $$I_{s}R_{s}$$ I understand the ...
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6answers
2k views

How can voltage burn out an LED?

I understand how a current higher than what the LED is rated for can burn out an LED, but how does something equivalent happen with voltage? If the correct current is on an LED but the voltage is too ...
1
vote
2answers
85 views

Why does this transformer draw so much current?

I've been working on a DC power supply to provide about 10 mA at 200 V. The simplest way (not dealing with a switching power supply) seemed to be using a transformer to step 120Vac up a little bit to ...
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0answers
44 views

How to Use Current Transformer

I have the the 3110-3000 CT: http://www.crmagnetics.com/Assets/ProductPDFs/CR3100.pdf What I am trying to do is get the current value in a wire, and the raw reading I get is consistently 1495 for ...
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1answer
22 views

Current limit on data out pins of Microchip HV5623

I am working on a project that uses the Microchip HV5623K7-G Serial-to-Parallel converter. As part of the design process I need to determine what would happen if the board I am designing is plugged in ...
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3answers
74 views

How do I know current across unknown load if I know voltage

If I know voltage across a load, but don't know load resistance, how do I know current going through load? Do I put a resistor of 1K and calculate? My voltage is square wave so multimeter only get ...
0
votes
2answers
70 views

Does a constant current source add to existing current?

If I have a circuit where one branch contains a constant current source (e.g. 2A), does the current leading out of the current source equal the current leading into it (e.g. 4A) plus the current of ...
2
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2answers
78 views

Using multiple current sense resistors in parallel to handle a high current measurement with cheaper resistors

I am measuring the current going to a motor using current sense resistors; however, in order to get a resistor that can handle the proper power, the price goes up way too much. My question is, can I ...
0
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1answer
40 views

Good way to switch AC/DC (Rectifier) in welder

I am building a homemade welder out of microwave oven transformers. I would like to have ideally an on off switch and then an AC/DC switch or just having one switch would work too. AC 120V 60Hz ...
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2answers
62 views

What is the maximum Power that Smartphones charge with? 2400mAh? [closed]

I have seen chargers rated at up to 2400mA, so I wonder, whats the max that Smartphones will accept while charging? I ask because I want to buy a charger that is able to supply the absolute max my ...
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2answers
28 views

RC circuit with lossy capacitor

This circuit simulate this circuit – Schematic created using CircuitLab can be regarded as an RC series circuit with a lossy capacitor. The time expression for \$V_C(t)\$ with \$R_2 \to ...
2
votes
3answers
390 views

Current flow through resistor and insufficient source

In a simple circuit consists of a source and resistor, according to Ohm's law, if 10V is applied to a 10 ohm resistor, the current flow through the circuit will be 1A. But what if the source in this ...
3
votes
3answers
76 views

Long 24V DC cable not working

We have a really weird issue which we just cannot get our head around. In high level: We have a unit which contains some electronics, we can access it with 4 cables 2 for power and 2 for ...
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1answer
34 views

Determine supply voltage for led from current limiting resistor

Everyone knows how to calculate the resistance of a current limiting resistor for a LED but is it possible to go the other way? (aka determine the supply voltage from the resistor's value) I ask ...
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0answers
30 views

Current sensor circuit design

Disclaimer - I have very little experience in analog circuit design/building. I want to build a current sensor with a wire-wound ferrite core (similar to this TA12L-100) placed around one of the ...
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2answers
79 views

General rule for current flow in op amps?

I'm a first year student doing elec eng. and I'm wondering about the direction of current in an op amp (Where the current flows from to where it is going). I'm wondering this so I can use KCL to find ...
0
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1answer
25 views

How to get constant current across varying Rload in h bridge

My I is a constant source of 10 mA from Vsupply of 50V, so my Rload can max at 5k at 10mA. I load is going both directions. My Isource is constant, but Iload is changing with varying Rload, why is ...
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1answer
37 views

Which 9 V DC Adapter Need for MB102 Breadboard Power Supply

Easy question. I'm a noob... I bought a MB102 breadboard power supply unit. But, it doesn't come with a manual. I need to get a 9V adapter for it. So, I'm not sure what I need. Does the 9V ...
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1answer
40 views

Why is Leakage Current Important when a MOSFET switch is “ON?”

Referencing ADG5206. ADI has specs for Drainage Current at the Source and Drain when the switch is OFF. They also have channel leakage for Source and Drain when the switch is ON. Why is it important ...
2
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2answers
55 views

When using nodal analysis of a circuit involving CCCS, how do you know which currents are entering and which are leaving?

I am trying to solve the following circuit: I believe the answer I'm getting for \$i_b\$ is wrong because I put it into LTSpice and I'm getting that \$i_b = -3.63636\$ This is my LTSpice diagram: ...
2
votes
2answers
322 views

Could you explain how this current measurement circuit works?

I have a schematic for current measurement, but I don't really know how can I calculate the output of it. The op-amps are on +-12V. The output of the circuit is 0.2*I(Rs) [V] (--> this is what I don't ...
1
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1answer
40 views

Arduino Controlled adjustable current 0-1A,18V

Hello Masters of Electronics, I'm civil ingeneer, electronics are big unknown to me, but it wakes up my interest. I would like to control proportional pressure with electronic proportional pressure ...
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votes
1answer
44 views

Voltage stabilizer input/output current

What is the relation between the input and output current of a generic efficient ( not just a zener diode) DC voltage stablizer ie: If the input voltage equals 15 V the stabilized voltage equals ...
8
votes
10answers
2k views

Is it really OK to supply more current than what the component is rated for?

In this heavily upvoted answer the answerer states that it is okay to supply a component with more current than what it's rated for. The analogy is that (paraphrasing here) "If Johnny wants to eat two ...
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votes
1answer
62 views

Why cant we test return neutral current with a tester? [closed]

The current that a load takes up comes into it from the live and reutrns through the neutral. We know that. We test a live wire by touching it with a tester in one hand and being in contact with the ...
1
vote
3answers
95 views

Proton current? and its potential effects in cars and circuitry

Is this statement true: "Within the (lead-acid) battery, the electric current is primarily due to proton (hydrogen ion) current which is in the same direction as the electric current." What are the ...
0
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0answers
25 views

Limit large currents in a small space?

I've built a variable voltage bench-top power supply from an old printer adapter. I cut off the output wires, and soldered in connections to a buck converter module and a potentiometer. The limit of ...
0
votes
2answers
90 views

NPN transistor: collector current flowing to emitter without connecting base?

I have a circuit where a LED has its cathode connected to the collector of my C8050 (or SS8050) NPN transistor, with the emitter grounded. Even though the base is left floating, the current is still ...
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2answers
32 views

Current sinking capability of HV507PG

I am new to this forum, heard you guys are great and helpful. I have been designing a nixie clock recently for my girlfriend's birthday. The tubes run at 170v and have a current rating of 2.5mA. I ...
0
votes
1answer
35 views

does biphasic wave mean current is bidirectional

does biphasic wave mean current is going bidirectional in a circuit?
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vote
1answer
60 views

how big my track should be to handle this current

I've read before that each 1 mm\$^2\$ of copper can handle up to 1 A. Is that true? Is there an easier formula than the one used on online calculators that requires temperature and such? To give more ...
-1
votes
1answer
59 views

Current consumption calculation and also battery life calculation [duplicate]

I'm a newbie, I need to know how to calculate the current consumption of circuit and also how do calculation of the battery life according to the circuit's current consumption? I'm using Li-Po ...
8
votes
4answers
948 views

Why are NPN Darlington transistors used to sink current?

I notice that NPN Darlington transistors are commonly used to sink current. Wouldn't it make more sense to use PNP for the purpose? This would avoid shunting the load current through both junctions at ...
9
votes
5answers
2k views

Is it OK to put LEDs in parallel? [duplicate]

I wonder if it's a good idea to put LEDs in parallel, as below: I've heard that it might not be because the voltage threshold won't be exactly the same for each LED, so they'll shine all with very ...
0
votes
2answers
68 views

voltage current converter by op amp circuit

I am trying to convert 5V to a constant current source for op amp I use AD822. for 250 ohm I use 180 ohm, so I should get a current of 28 mA. I verified when Rload = 0, 28 mA across negative ...
0
votes
1answer
30 views

TA12L-100 current sensor max current

I want to buy this current sensor from eBay. I couldn't find how it works, but I presume it works like the other ones through induction. On many sites it says it has a maximum current of 5 amps, but ...
-1
votes
2answers
52 views

How does one determine the voltage of a node?

This sounds like a very straightforward question, and probably has an obvious answer. I've read a section in a physics book on electricity, I've read a textbook on DC and this simple concept seems to ...
0
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2answers
24 views

Potential lose of time-dependent currents in presence of static magnetic fields

A time-dependent current (either DC or AC) that creates a changing magnetic field around the wire, in absence of other materials, only lose current in heat proportional to ohmic resistance of wire ...
-2
votes
1answer
58 views

At what capacitance and voltage are capacitors harmful? [closed]

I'm currently building a taser from scratch and would like to know which capacitor to use.
-1
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0answers
18 views

Wheatstone bridge output to 1-5v

ive been given a question that i have to convert the resistance output from an RTD to a 4-20mA signal. Firstly, i am going to convert the resistance from the RTD into a voltage signal, by using a ...
0
votes
2answers
53 views

Switching converter current mode control - load disconnect problem

I'm building LED driver based on current mode control buck converter. My question is quit general. If load is disconnected then output capacitor voltage shoots up. If load is reconnected it gets ...
0
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1answer
40 views

negative voltage sources and KVL

I have the following circuit: simulate this circuit – Schematic created using CircuitLab If I choose clockwise current direction then KVL gives me: $$10V+5kΩ*I-0.7=0 =>I=-1.86mA$$ If ...