Voltage is the unit of measurement for electronic potential, from one point location to another.

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Electric warning signs question

I've always wandered why do the warning signs show the voltage, not the current. I mean, it's the current that kills you.
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15 views

What are the risks of touching a positively charged lead to a negatively charged lead? [on hold]

this is my first time asking a question here so hopefully I frame it correctly. I have two electrodes that are charged to opposing positive/negative potentials. I need to place them in fairly close ...
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3answers
53 views

If we connect a long wire to a battery, will battery produce more electrons?

I actually have three related questions: An open circuit chemical cell separates charges creating a surplus of electrons on its negative terminus and a shortage of electrons on its positive terminus. ...
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1answer
35 views

Magnetic Wire Doesn't conduct Electricity

I recently bought a 22 and 30 gauge loop of magnetic wire from radio-shack. The loops of wire were colored differently (if this makes any difference) and on the package it noted how these wires were ...
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6answers
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Could someone intuitively explain to me Ohm's law?

Could someone intuitively explain to me Ohm's law? I understand what voltage is and how it is the electric potential energy and that it is the integral of the electric field strength etc. I also ...
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2answers
43 views

Capacitance and Voltage Drops

Let's say that Switch $S$ is closed. I have a conceptual question: If a stream of particles acquire a potential difference upon exiting the battery, why will they lose some of that potential ...
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1answer
39 views

Spherical Magnet Inside a Solenoid

When passing a bar magnet through a long solenoid why is it that the induced emf when the magnet is in the middle of the solenoid is zero? And if a spherical magnet is put inside the solenoid, will ...
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1answer
81 views

Measured voltage on coil

I have a simple circuit of coil with inductance L $$u_c(t)= -L\frac{di}{dt}$$ and AC source with output voltage $u_s$ What is actually measured by the voltmeter ($u_c$, $u_s$ or $u_s - u_c$)? If ...
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1answer
28 views

Showing $\frac{\delta V_{out}}{V_{out}}=\frac{\delta R_2}{R_2} \frac{R_1}{R_1+R_2}$ [closed]

Consider a voltage divider with $V_{out}=V_{in} \frac{R_2}{R_1+R_2}$. Show that for a small change in $R_2$, the voltage divider equation is: $\frac{\delta V_{out}}{V_{out}}=\frac{\delta R_2}{R_2} ...
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1answer
21 views

Relation between Power, Voltage and Current when one or more of them is amplified?

Power(P) = Voltage(V) * Current(I) If voltage or current is amplified or multiplied what happens to power and current. Does this affect in increase or decrease in power and current values or does ...
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0answers
24 views

Li-ion Battery charging

Why are constant current mode and constant voltage mode needed when charging Li-ion batteries? Why do we apply saturation charge even after the cell voltage reaches 4.2V? What exactly is 'I-sense' in ...
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3answers
49 views

Defining Reference Directions for Voltage and Power (sign convention)

My professor decided to use the above reference directions when calculating power in circuits. He says that when power > 0, power is consumed. When p < 0, power is generated. This definition is ...
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3answers
64 views

Why Voltage Drop is not Influenced by Resistor Value?

To my understanding, if a resistor reduces the potential energy of the current across it, then the current that leaves the resistor will have less potential energy and thus, less pressure or voltage. ...
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1answer
44 views

What is the equivalent of the “amount of fuel” for a battery?

I am trying to make a performance diagram of an electrical powered device vs range, speed, etc. I want to compare it using the equivalent of fuel for a battery? I am not sure if it is just voltage... ...
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2answers
54 views

Both plates of capacitor have positive voltage

If both the plates of a capacitor are connected to positive voltage (say, one is +10V and the other is +5V), but there is a voltage difference between the plates, will the capacitor be charged? And ...
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7answers
116 views

Why Two Equal Resistors Cut Voltage in Half?

I've been reading several books on electronics, one of them called "Electronics All-In-One For Dummies - D. Lowe (Wiley, 2012) BBS". It states that if two resistors of the same value, no matter the ...
2
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1answer
49 views

Why there's any voltage on P-N junction in diodes?

If all electrons here have their counterparts in protons, on both, P and N sides, then why there's any voltage (built-in voltage, on the bottom of the image)? Both sides should be neutral, shouldn't ...
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1answer
52 views

A falling steel beam - Maximum induced voltage [closed]

I'd appreciate it if someone could explain how to answer this question: A 2 m long steel beam is falling from a height of 12,5 m. During the fall, the beam is oriented in an east-west direction. ...
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1answer
55 views

Transformers - Why more coils in second coil causes more voltage [duplicate]

I am learning about magnetic induction and transformers. I have coil1 which uses AC to create an oscillating magnetic field. I have ...
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1answer
72 views

Deriving Voltage from Electric Field

I'm trying to derive the point charge equation for voltage by integrating the point charge equation for an electric field over distance ($dr$) traversed:$ \int (KQ/r^2)\cdot dr$ This is my ...
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0answers
24 views

Why does electrolysis require a base electrolyte instead of an acid electrolyte?

I am in the process of using electrolysis to remove rust from some old tools. This is the process where you submerge the rusted item in a bath along with a sacrificial piece of metal. You connect a ...
0
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1answer
38 views

When do I use the various power-related equations? [closed]

Can someone please tell me when it is appropriate to use the equations $P=IV$, $P=I^2R$ and $P=V^2/R$?
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2answers
40 views

Current lagging voltage by more then 90 degrees

According to Wikipedia https://en.wikipedia.org/wiki/Leading_and_lagging_current An alternating current that reaches its maximum up to 90° behind the voltage producing it is said to be lagging. and ...
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1answer
49 views

Comparing voltages of Parallel and Series circuits

There are two electric circuits. Resistor 1 ($R_1$) connected with resistor 2 ($R_2$) by series circuit $R_1$ connected with $R_2$ in parallel Each of the circuit has battery with emf and the ...
3
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1answer
94 views

What is fatal? Current or voltage? [duplicate]

I have been searching this answer for quite a while. I asked my physics teacher and he said it is current that causes death. A friend of mine, who is a EE student, and his answer was voltage. When i ...
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3answers
94 views

Why can't unequal current sources be connected in series?

Imagine two power sources: PS-1 that can supply $5A$ at $100V$, and PS-2 can supply $10A$ at $40V$. Due to conservation of charge and Kirchoff's current law (KCL), this is incorrect, and would lead ...
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3answers
341 views

Why does my measured I-V curve for a film of aluminum suggest high resistance?

I plotted the I-V curve between two points (few microns apart) on a thin aluminum film. I expected this metal to be a conductor and have a much lower resistance, but the slope suggests that it is ...
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2answers
35 views

Power in a circuit why is V constant

In deriving the power of a circuit we can do the following: $$\text{P}=\frac{dw}{dt}=\frac{dQ}{dt}\frac{dw}{dQ}=\text{IV}$$ But this assumes that $V$ (since $w=VQ$) is a constant. Why can we assume ...
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1answer
81 views

What really happens in a electric circuit?

How do electrons behave in an electric circuit? There was a question before about a voltage drop which was interesting, but I can not participate in that discussion, so I am writing this question ...
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1answer
85 views

Why high voltage transmission lines?

This is a question which I seem to have tackled multiple times, solved each time after reading a dodgy internet explanation, then partially forgotten about and retackled half a year later. It is time ...
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2answers
72 views

Does voltage drop occurs with zero load and zero resistance

Imagine a circuit consisting of just a battery and conducting wires which have zero dissipativity so that there is no loss of energy( Zero resistance). If the wires are connected to both terminals ...
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3answers
255 views

Why capacitance is given as constant value in Farads, and not as max charge in Coulombs?

The equation for capacitance is $Q=CV$ or $V={1\over C}Q$. I don't understand what is the physical meaning of this "$C$": Does the charge in a system changes linearly with voltage under all ...
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1answer
53 views

Exact Relation between voltage and current [duplicate]

I apologize before hand if this seems too naive. I'm having a really tough time understanding the relation between voltage and current. I read that 1 Volt is the amount of work done to move a $1As$ ...
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1answer
49 views

Influence of applied voltage to an electron of a metal

I would like to ask what would happen to the potential well of an electron being trapped in a metal? If I apply a voltage trying to accelerate the electron out of the potential well. Would It make the ...
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1answer
55 views

Solving kinetic energy exercise through electrical work formula instead of voltage formula?

While studying electric potential, I run into an issue on exercise 43 of Chapter 24 of Fundamentals of Physics 8th ed. Vol. 3 (Halliday et al.). The exercise states the following, paraphrased: A ...
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3answers
116 views

Voltage drop = more electrons on one side of resistor

I have been asking myself this question for a long time now. Suppose we have two resistors in series connected to a voltage source. Simply put, does the voltage drop on each resistor mean that there ...
2
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3answers
132 views

The Difference Between voltage and current

I know that this question has been asked many times before, and I have read over several of the threads asking this question, but they do not include the gripe I have with my problem of understanding ...
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3answers
91 views

Voltage in a parallel circuit [duplicate]

Why is voltage same across a parallel circuit? I mean what makes the voltage remain same across two resistors connected in parallel? If an electric heater is connected in parallel with a bulb and ...
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1answer
26 views

Finding voltage between two points in space

If electric field vector is defines as : $\vec{E} = \frac{V_0x^2}{a^3} \vec{i_x} + \frac{V_0y}{a^2} \vec{i_y} $ where $V_0 $ and $a$ are known constants, $\vec{i_x}$ and $\vec{i_y}$ unit vectors of ...
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1answer
80 views

Why is voltage added when batteries are connected in series but not in parallel?

As I understand, the different voltage between two object is caused by the total different charged between two object. Thus, the higher extra electron between two opposite charged object, the higher ...
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2answers
52 views

Is it possible for electrons to carry more than one charge?

Sorry if this has been asked before. Could also be a really basic question (new to electrical study). I am a bit confused about the relationship between electrons and charges. So what I understand is ...
3
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3answers
148 views

What is the physical meaning of electric potential, potential difference, and voltage?

When resembling the electricity flow through a wire to people walking through a street: electrons are people, current is the number of people, resistance is the barriers on the way. But what is the ...
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1answer
25 views

Can a current source provide Voltage to a resistor?

We know that the tension between a perfect current source is 0 We have Va-Vb= 0 but we also have by ohm's law Va-Vb=RI=5V so 5 = 0?
2
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4answers
237 views

Justification of root mean square [duplicate]

In the top answer to the question Why do we use Root Mean Square (RMS) values when talking about AC voltage, the following was stated: This RMS is a mathematical quantity (used in many math ...
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1answer
25 views

Variation of Peak Current and Peak Voltage with Capacitance in an AC circuit

The relation of Peak current, Peak voltage and Capacitive Reactance in Alternating Current is given by: $$i_m=\frac{v_m}{X_c}$$ and $$X_c=\frac{1}{C\omega }$$ So if we have a circuit with a ...
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1answer
52 views

Voltage divider example [closed]

I have the following voltage divider circuit: Now, my goal is to find U_{L}. Altough, I know already the solution (U_{L}= ...
1
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2answers
58 views

What really causes terminal voltage?

In class we see how a current reduces the voltage across the battery if it has internal resistance. And we see that Vterminal=EMF-Ir. We don't really see the theory behind this, and I went on to ...
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0answers
30 views

Propagation of Error Formula

I did a lab, and found the Hall voltage for different currents. From these, I was also given the direction, and magnitude of the magnetic field. I need to find the number of charge carriers per ...
4
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2answers
259 views

Voltage drop due to a resistor

I'm afraid this question is going to sound rather dumb but here it is: Suppose I have a very simple circuit: one battery and one resistor. The sum of the voltages in this circuit has to equal zero. ...
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0answers
30 views

Alternating current means alternating voltage?

We get supply from an AC generator which provides AC current.It is by the way the generator works that the current is alternating. Because of electromagnetic induction and the fact that the coil is ...