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

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0answers
30 views

How can I measure ripple of any signal using MATLAB? [on hold]

Is there any method to calculate ripple of signal in MATLAB code?
0
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1answer
79 views

How much current actually passes along household neutral?

My home has 3-wire single-phase supplied from the power company (Massachusetts, US). Red and black are separated by 180°. Both are 120 V from neutral (white). And in my electrical panel, neutral ...
0
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1answer
36 views

Increasing USB 5V current the right way

USB2 is limited to 500mA. If you want more current you need an external PSU to pump in more juice. What would be the proper way to add another 5V PSU to the system? Connect the 5V from the PSU to ...
0
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0answers
41 views

Liquid spill on MacBookPro. How to test magsafe dc-in board? [on hold]

I hope this is a proper place to ask this kind of question... A full glass of champagne was spilled on my MacBookPro model A1278 and took me some time to realize... After 10min, I've turned it ...
0
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1answer
43 views

Known voltage/current source

I am working on an EVM for an electricity meter. Its manual says the EVM requires a known voltage and current source for the calibration. I bought a power supply and measure the output of the PSU by ...
-2
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1answer
54 views

Circuit breaker vs. electric heaters

Let's have a household with 230 Volt AC supply. What happens with the current if I start to gradually activate more and more (purely) resistive loads, like electric heaters and ovens? Because I=U/R, ...
1
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0answers
39 views

Small overdose in current — dangerous? [duplicate]

(I have a feeling that this question may be off-topic here because it is so utterly, enormously basic, and hardly related to engineering at all. Please bear with me...) My phone came with a power ...
0
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1answer
71 views

Calculate current using compensation

simulate this circuit – Schematic created using CircuitLab Okay, first I'd like to apologize if this question seems stupid, but I'm preparing for an exam, and don't know how to solve this ...
0
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1answer
57 views

Supply voltage drops AFTER connecting to device [on hold]

I have a 19V 2.1 amp (power mentioned is 45 watt) laptop adapter connected to a 19V 2 amp laptop (in description power mentioned 10.2 watt). When I plug the adapter, the multimeter shows the rated ...
2
votes
3answers
60 views

Current drawn by a permanent magnet DC motor

I have been working with PMDC motors for a while now. In these motors, as the load increases current drawn by the motor also increases. I was just wondering what is the theoretical reason behind this ...
-3
votes
1answer
59 views

Ohm's Law Calculation

Just a quick quesiton. How much current if Voltage is 12 with 2 Ohm resistor's? If you can explain to me how you get the answer, that'd be great. Thanks.
1
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1answer
59 views

What is the current gain of this op-amp circuit?

I just happened to see this circuit in some lecture slides and I thought I could solve it. Unfortunately, I've been trying to check my result with an ideal simulation in LTspice and all my attempts ...
2
votes
8answers
585 views

How do households get their power?

I'm a little confused about the whole kilowatt hour thing. I get its 1000 watts in 1 hour but I don't get how you figure out how much voltage and current is running through the house. I did a little ...
0
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0answers
19 views

How to rectify the power line for leakage current based electrical shocks? [duplicate]

In May 2014, I had purchased Samsung LCD TV with two pin mains cord. I used to get electric shock like feeling when I touched the metal body part of it or the HDMI port (any other connected ungrounded ...
1
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0answers
36 views

Analyse data discrepancies: Efficiency of wire vs current

Please help me explain why the efficiency of the wire does not follow a distinct path (ie R^2 value is low). Graph 1 Efficiency of wire vs current: http://postimg.org/image/p49bzm4ab/ Is is to do ...
0
votes
1answer
37 views

How to provide enough current for my GSM circuit, and still use a LiOn battery?

I am very new to electronics. I am building a simple GPS tracker prototype circuit that uses a 3.7 volt 500mah lithium ion rechargeable battery. The circuit has 2 major components: a simple ...
1
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1answer
86 views

Don't understand spec sheet

I'm planning to buy a photo-interrupter, and I had a look at the spec sheet, but I didn't see much on the current/voltage of the device. I was thinking that it could run on 20mA, but I am confused ...
0
votes
1answer
51 views

Measure 208v single phase with Current Transformer

I have a single phase 208v circuit that I want to measure the amps on. What is the proper way to measure the amps? This is for a connection with 2 hots and a ground wire, no neutral coming from a ...
1
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4answers
205 views

How many LEDs can you chain in serial?

Theoretically, on a 12v with a max of 10w power line, how many LED's could you chain in serial before the LEDs further down the chain begin to dim? Where the LEDs have a forward voltage of 3.2 - 3.5 ...
-2
votes
1answer
79 views

Battery Current Stabilizing [duplicate]

So, from I can tell from the answers I received to my previous questions, if I want to lower the output current from a battery, I could put a resistor in series with my circuit. But wouldn't that ...
-2
votes
1answer
46 views

How to increase current output of a multiplexer for activating a relay

I want to make a multiplexer for my project which needs 24v dc to operate. I am using an OR Gate IC for generating an output. My 4 gate inputs are connected to 6V battery power and I am getting a 6V ...
0
votes
3answers
95 views

Current flow through a battery

So this might be a stupid question and I really should know the answer to it but I am having difficulties with a circuit I have made to drain a battery. The basic idea of this circuit is that I have ...
0
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1answer
70 views

Controlling current in a PWM circuit

I have a PSOC Cypress board which generates a 5V PWM signal to drive a laser diode. The idea is to design a programmable pulse which I could control the on-time period and current in the pulse. The ...
0
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2answers
67 views

Maximum op-amp output current

Im looking to drive an LED, but am not sure if i should use an op-amp or bjt configured as a switch. Is it possible for an op-amp to source roughly 10mA; the current needed to drive an LED in series ...
1
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4answers
130 views

KVL loop current direction convention--should be same in all loops?

Do we have to take the same sense of direction for loop current, like clockwise, in each loop when applying KVL to a circuit or can we take different directions in different loops? If we must take ...
0
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1answer
30 views

Current Injection Via Jumper Design Help

I am currently designing a circuit that uses a 5V 2A power brick. The circuit requires a current source and I have seen good efficiency with Ohm's Law. The current is variable through a 2k ...
0
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3answers
87 views

Current capacity of batteries wired in parallel

I'm wondering what would happen to the mAh when I connect 2 5000mAh batteries in parallel. Would the mAh over all be 10000mAh?! simulate this circuit – Schematic created using CircuitLab
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0answers
38 views

Voltages and Current, which is important [duplicate]

I got my laptop adapter busted, it outputs 19V 3.42A, and I am not sure the reason why. My laptop takes in 19V but at 2A. Maybe the adapter was not the right fit. So I was thinking to build my own. ...
0
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1answer
43 views

Understanding the input specifications for a laptop adapter [closed]

The sticker on my laptop adapter claims the input should be INPUT: 100-240V~ 2.5A(2,5A) 50-60Hz What does all this mean? Here are a couple specific questions: Can the adapter accept anywhere ...
0
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3answers
128 views

How are multi LED flashlights wired to control current w/o resistors or regulator?

I have several cylindrical LED flashlights that have a large number of LEDs in them (the one I'm looking at has 9, which I think is typical.) They take 3 AAA batteries, wired in series, to give ...
0
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2answers
73 views

Differences between 5V DC 350ma vs. 450ma [duplicate]

I have two A.C adapter chargers giving an output of 5V DC 350mA and the other one with 5V DC 450mA. Is it possible that I could ...
0
votes
1answer
85 views

Russian variable resistor datasheet

Can you please help me find datasheet for this 2.2 ohm variable resistor. I want to know if it can tolerate 20 amps. If you recognize the logo that would help a lot.
2
votes
2answers
96 views

Measuring current around 20 amps

I have an electrolyzer that works with car battery (12 volts DC) and draws current around 15 amps. I have a digital multimeter that can measure 10 amps at most. So how can I measure the current? Maybe ...
3
votes
4answers
657 views

How to get more current from 555 timer?

My power supply is filtered regulated 5 volt 500 mA . I am using a 555 in monostable mode to switch the motor on for a certain amount of time after the 555 is trigerred. (The 555 is being trigerred by ...
0
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2answers
135 views

“Ground” vs. “Earth” vs. common vs. negative terminal

This may just be me not having a degree in electrical engineering or electronics, but the whole notion of "ground" and "earth", when used in electrical circuit diagrams (especially integrated ...
0
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1answer
63 views

Bipolar transistor switch base current calculation example from PEFI seems wrong?

I'm reading through Practical Electronics for Inventors, 3rd edition, on bipolar transistors, and they provide this example of a transistor switch: I'm a bit confused by the calculation at the ...
0
votes
1answer
52 views

Heating coil over-drawing current

I am currently designing a circuit that includes a nichrome coil used as a heating element. The wall adapter is 25V 5A DC, which leads to different buck converters that takes it down to the ...
0
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1answer
108 views

Understanding ground symbol

If ground is a reference point and it is not physically connected how can it protect someone touching the wire from electric shock (I probably misunderstand what that symbol really means)
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2answers
118 views

How current flows

I've read about how current flows and I am confused. I probably don't understand it correctly so I am asking 2 questions If I connect 2 charged sides of battery by copper wire and I touch that wire ...
1
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1answer
54 views

Understanding current flow in example

When I have series circuit with 3 light bubbles the voltage in second should be less than in first and the voltage in third should be less than in second. Conventional current flow is from positive to ...
5
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3answers
355 views

Will 74HC595 as LED sink damage LED when pin goes high?

If used as a LED sink, what happens if a 74HC595 pin goes high? Might the LED blow? I expect that when a pin is low, current will sink and the LED will light. What about the opposite condition? ...
3
votes
1answer
99 views

Help interpreting TIP127 datasheet

I'm trying to build a constant current 2A amplifier using a TIP 127. To be honest, I have a lack of transistor knowledge. I decided to analyze a few existent circuits with a TIP127 and the datasheet. ...
3
votes
1answer
243 views

Not sure if my calculation is correct, can anyone check this RC circuit for me?

Hello everyone, so in my book I decided to do this practice question but failed to notice that the answer was not given in the back of the book. If anyone can help me confirm my answer I would much ...
1
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1answer
50 views

Switch current rating - actually current or really wattage rating?

I'm trying to build a dummy load for some power supply testing using some very large power resistors. Basically I will wire up the resistors in parallel and connect more if I want to decrease the ...
0
votes
2answers
170 views

How to amplify DC Voltage to be used like supply to 2km?

I want to turn on a device away from the voltage source to 2 kilometers. My device operates at 24VDC or 48VDC / 35W. I need to know how is it possible to amplify the voltage from 24Vdc to 240Vdc or ...
0
votes
2answers
72 views

Resistors in series current question

According to Wikipedia, the current of resistors in series will be Vin/R1+R2. Now I could be over thinking this but is that the current that you'll get out or is that just used for determining the ...
4
votes
2answers
204 views

Current boosting problem with 78xx

I've built a PCB with a 7805 based power supply on it. I tested the other parts of the PCB on a breadboard before I had the PCB made, but as the power supply circuit looked straightforward, I just ...
2
votes
1answer
134 views

Measuring Remaining Battery Life

I am working on a project testing alkaline batteries and need a way to quickly measure remaining battery life. I would like to be able to estimate mA-h remaining in the battery. If I measure mA-h over ...
1
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1answer
136 views

Is this current measurement solution okay?

One wishes to measure the RMS current (12A max.) drawn by an AC motor using a PIC16F887 at intervals of 1 second. One cost effective solution I am considering is using a current transformer, a bridge ...
0
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1answer
48 views

Can an amplifier deliver a higher power for a short burst as opposed to continuously using the same circuit

I am struggling to understand the fundamental power requirements for an amplifier. If I want to deliver 56 V rms to a 7.5 Ohm load I can use P = V^2/R and find that I need 418 W rms. Requiring a ...