It's a measure of how much an conductor opposes current flowing through it. It can also refer to a part of a circuit, which has a non-negligible resistance value.

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16 views

Heat output element

I'm building a little quiz game in Arduino and I already have it displaying a multiple choice question and people can answer by pressing pushbuttons. But anyways now I wanted to know if it's possible ...
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2answers
75 views

resistor's resistance value in any circuit [closed]

how can I find resistor value in any circuit ? please don't tell me anyone about colour code only tell How do I know that there used to resistor this.
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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 ...
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1answer
51 views

Explain this line of working when solving for the maximum power of a load resistor

Please, can you explain this line of working from the maximum power transfer theorem: For maximum power dissipation in the load, the condition given below must be satisfied $$\left. ...
3
votes
1answer
42 views

Inductor value given in OHM/Amp

I've been trying to figure out the inductance in Henries from a schematic of a Rabbit Microprocessor development board, however, instead of finding an inductance value over the components in question, ...
0
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3answers
56 views

Strength of a pulsed electromagnetic field

Forgive me if my question sounds a bit naive: I have built a coil (no solid core) out of an insulated copper wire, and I calculated that it has 8 ohms of resistance. I tried it and it gave me the ...
2
votes
2answers
112 views

Check my math: Calculating the size of extension cord needed

I think I've done this right, but I don't trust myself. Will you check my math and see if I'm right about this, or correct my error if I'm wrong? The facts I have a device (A Yamaha Stagepas 400i ...
0
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1answer
61 views

What is a 'normal' resistance level for a closed switch?

In a closed contact or a closed switch, theoretically, the resistance should be zero, but in actual measurements the resistance is very close to zero but not zero. So my question is: What is a ...
2
votes
2answers
145 views

High resistance voltage divider

I am trying to create simple variable voltage divider circuit, with several constraints that are causing me to look for alternative solution. Constraints: The input voltage is 1.5 V Maximum R1 is 5 ...
0
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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.
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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 ...
0
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3answers
113 views

Why is voltage higher at positive wire instead of negative wire in this example?

If electrons travel from "-" to "+" and voltage decrease going through resistor why is voltage higher at positive wire instead of negative wire?
2
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2answers
162 views

Compute for resistance (Resistance circuit)

Hi how do you solve this problem? I am confused. simulate this circuit – Schematic created using CircuitLab Find \$R_{AB}\$, \$R_{CD}\$, \$R_{EF}\$, \$R_{AE}\$ I came up with this: ...
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7answers
256 views

Understanding resistance in open and short circuits

I am continuing to try to learn a little about Electronics and I came across the following problem for which I am not sure I completely understand the calculations. In other parts of the book, they ...
0
votes
3answers
63 views

How to measure the resistance of digital potentiometer AD5241 in circuit when power on

I have designed a transimpedance amplifier including a digital potentiometer AD5241. The circuit is showed below. I want to test the AD5241 to make sure it works as designed. simulate this ...
0
votes
0answers
30 views

Solar charger under rapidly varying conditions/impendance

My solar equipment consists of: Solar panel capable of: 20V Peak / 3.6A Peak Li-Ion Battery pack: 8.7V, 9Ah, (2S3P setup) My solar charger setup consists of: 5A DC-DC BUCK converter (XL4015) ...
4
votes
6answers
218 views

Given a known power supply, what are safe ranges for the volts/amps/ohms of connected components? [duplicate]

I'm new to hardware and am coming from a software background. I have an SoC that will be powered by a supply generating 5V and 1A. I'm trying to figure out what are the safe ranges of volts/amps/ohms ...
0
votes
6answers
290 views

Why are resistor values constant in the face of changing voltage and current?

Small question, I see that resistors are labeled in certain increments (e.g 5, 10 50 Ohms), although a resistor outside of a circuit is completely without voltage and therefore current. Does this just ...
0
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3answers
104 views

Why doesn't linear resistance scale proportionally with the square of length?

I have an in depth question about basic proportionality of resistance. Why doesn't it scale with the square of length? I ask this because what is causing the potential difference on two leads is ...
0
votes
0answers
55 views

Inducing Eddy current in wet clothes

Is it possible to induce eddy current in wet clothes and dry them using the resistance heat generated? I don't want to connect any wires to the clothes.
1
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1answer
87 views

Understanding a power source's internal resistance?

I have a mechanical system that requires a certain amount of electrical power. Now, when I calculated everything I did not include the internal resistance. For example: I calculated that the ...
0
votes
2answers
83 views

Why can I put a resistor at either lead of this LED and still see its effects? [duplicate]

Just to add a little bit of context to the question, I am using an Arduino Uno and a breadboard. I have a 5V power source running to the positive (longer) lead of an LED (rated at about 2v and 20mA). ...
0
votes
6answers
85 views

How do I figure out the exact voltage and current needed for a part?

Whenever I look for parts in my local electronics store, I come across parts(e.g a speaker), that have just a power rating stated(e.g 2W). While I know how to calculate power,voltage, resistance etc, ...
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1answer
52 views

Proper resistor for simple circuit

I have a potentially stupid question, but I have no idea how to handle the problem. I want to use 9V battery with a diode that requires 5V. So I need a resistor. How do I find the resistance if (as ...
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2answers
52 views

Finding load resistance to achieve max power transfer

1) So, to find Thenevin equivalent resistance, R-Th, I disconnect R_L and disable the voltage source by shorting it out. ...
-1
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3answers
97 views

Conductivity of plastic, wood and leakage current of laptops

Back around 2010, there were incidents where the surface of laptops have conducted 20-100V and have electrically shocked users. There is no doubt most of the newer laptops still conduct a continuous ...
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2answers
123 views

Using audio amplifier speaker output to drive an electromagnet

My first time here as a poster so forgive me if I make a misstep... I am building a coil (22swg enameled copper wire, about 500 ft), some 4in inner diameter of the bobbin, 1" wide, will have ~ 450 ...
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2answers
84 views

Use of inductors vs resistors

Why would we place an inductor in series with a lamp, rather than just a resistor? I'm sort of thinking it has something to do with being able to control voltage to the lamp, without effecting ...
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2answers
43 views

Non-parallel, non-sequential circuit

This is the circuit: I've simulated it and got a current of 30.76mA at the voltage source (5V). With this I've calculated the total resistance to be 162.5 Ohm. Each resistors is 100 Ohms big. But ...
0
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1answer
65 views

Two-port network: find fundamental parameters

What is the easiest method to find the ABCD parameters? I tried replacing the middle part of the circuit (R2,L,C) with an equivalent impedance and then finding U2 depending on U1, but it is very ...
0
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1answer
242 views

How to calculate the resistance of a complicated circuit?

I learned in high school the basic rules of how to compute resistance between two points, given a network of resistors. You try to rearrange the circuit so into parallel parts and series parts, then ...
5
votes
1answer
130 views

Kelvin “4 Wire” Resistance PCB Design Questions

I am designing a PCB that will utilize 4 wire measurement for 40 or so test points. A little background here - day to day I troubleshoot PCB's to component level, I'm an electronics technician and ...
4
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2answers
137 views

Resistance measurement voltage - multimeters

What voltage/current is applied by modern multimeters to determine resistance?
7
votes
3answers
590 views

Resistance, and learning for beginners

I am building an electrified "fence" of sorts to keep slugs out of my raised garden beds. The "fence" consists of two 18ga galvanized steel wires, stapled to wood and connected to a 9V battery. The ...
1
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3answers
121 views

Unbalanced pi- attenuator - Problem with simulation

I've been trying to simulate the asymmetric pi-attenuator example on this page with different source and load impedances: http://www.electronics-tutorials.ws/attenuators/pi-pad-attenuator.html I ...
13
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3answers
1k views

Will doubling thinner wire in lieu of thicker wire work?

I've been needing a jumper cable for a while and have plenty of 10 AWG copper wire lying around. From what I've read, 6 AWG wire is recommended for jumper cables. I want to make a 7 foot cable. So, ...
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3answers
154 views

Calculate voltage, current and resistance in a complex mixed circuit

How can I calculate voltage and current on each resistor (especially R5) in this circuit? What is its overall resistance? I have no idea how to do this.
1
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3answers
55 views

Controlling power?

From Ohm's law, we can control the voltage and current of a circuit by changing its resistance? Say we have a power source of 10kW, we can increase V by increasing R, and we can reduce V by reducing ...
0
votes
4answers
131 views

How can I minimize the variance in voltage drop across transistors - or eliminate transistors from this design?

I have a fairly simple circuit that I'm using with an arduino to measure the impedance on a very low-resistance circuit. The user plugs in a device at A and B and the arduino can compute the ...
6
votes
1answer
560 views

What does “OC” mean?

My Bluegiga WT-32 manual ("Stereo CODEC ADC characteristics" table) says: Allowed Load --> Resistive, min.:16(8)Ω , max.: OC What does OC mean in this case?
0
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0answers
56 views

Minimum AC voltage that causes nerve damage?

What is the minimum AC(50-60Hz) voltage that can do harm/nerve damage? I know that a few hundred volts (even 100?) has been documented to cause nerve damage that resembles a crush injury. I also know ...
0
votes
2answers
81 views

What is the strain gauge resistance variation of a 3-wire loadcell?

A 3-wire loadcell have two strain gages with a no load resistance of R. When a load is applied, the resistance of one strain gauge will change to R+dR and the other will change to R-dR (because one ...
2
votes
2answers
148 views

Why do you need a thicker wire when wire length increases?

Question: So far I've found that the thickness of the wire influences the resistance. A thicker wire has less resistance. Also, the length of a wire has a linear correlation with the resistance. 2x ...
-1
votes
2answers
72 views

If resistance is very high?

$$ V = IR $$ If there is a conductor with very low resistance, moving in a magnetic field, will it induce low EMF = IR? And a high current? Im confused at that point... Lets assume a conductor ...
0
votes
4answers
146 views

How does a potentiometer work?

A lot of places where I've read explanations about potentiometers either go into so much detail or they're so superficial that I don't understand the actual concept behind it. How would you easily ...
1
vote
1answer
84 views

Minimum electrical resistivity of contact material for human protection from lightning

The context of the question is camping and sleeping outdoors in the unprotected elements. If you’re sleeping in a tent close to the ground, and lightning directly strikes your tent or the vicinity ...
0
votes
1answer
39 views

Is the Delay in Strain Data Due to Capacitance?

I have designed a sensor board which gives a strain o/p based on wheatstone bridge principle(change in stress is measured through change in resistance). But the starting value is not at zero level,it ...
4
votes
6answers
1k views

Over 10,000 amps?

Is it possible to have a 5 meter wire that has 10,000 amps or more current flowing? I assume this can be done with a step-down transformer and the voltage could be 2V and lower... I assume that most ...
2
votes
3answers
231 views

Input resistance of a transistor circuit

I have a question from the razavi's microelectronics book: I'm puzzled because in the solution provided, the first line states that: "We know that the input resistance Rin = R1||R2||\$r_π\$." ...
3
votes
1answer
111 views

Use water as a conductor for a circuit powered by 1.5v battery

I've tried to create this quite simple circuit. V1: 1.5 v (AA battery) LAMP1: 1.5 v, 0.2 a (E10 incandescent light bulb) "Salt water": 10 ml regular water + 1 g salt When I connect the wires ...