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

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I don't understand what we really mean by voltage drop

This post is my best effort to seek assistance on a topic which is quite vague to me, so that I am struggling to formulate my questions. I hope that someone will be able to figure out what it is I'm ...
0
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1answer
30 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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3answers
362 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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2answers
1k views

Why does vaccum have a nonzero characteristic impedance towards electromagnetic radiation

OK, so the characteristic impedance is calculated "as square root of the ratio of the permeability of free space (µ o ) in henrys per meter ( H/m ) to the permittivity of free space ( o ) in farads ...
2
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3answers
11k views

How can I theoretically describe the potential between two capacitors in series?

Suppose to have two capacitors in series: The voltage in the middle point will be: $$ V_X = V_1 \frac{C_1}{C_1+C_2} $$ How can this be explained? It's been asked in electronics, and explained in ...
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0answers
46 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 ...
0
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3answers
362 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. ...
2
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3answers
4k views

Does the 'mAh' rating of a battery have something to do with its power?

I'm curious about the 'mAh' of a battery: how can this impact the power of the battery? I've done some research on the internet, and most of the articles I found explain about the 'amount of charge ...
0
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1answer
47 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... ...
0
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2answers
205 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 ...
0
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7answers
406 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
58 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 ...
0
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1answer
52 views

Influence of a Capacitance Matrix of a voltage measurment

I am having a problem in understanding how in a multiconductor system the Capacitance Matrix influences the measure of voltage between two electrodes. In the case that interest me we have 4 ...
1
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3answers
362 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 ...
4
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3answers
17k views

Current without Voltage and Voltage without Current?

At school I've always learned that you can view Current and Voltage like this: The current is the flow of charge per second and the Voltage is how badly the current 'wants' to flow. But I'm having ...
0
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1answer
93 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. ...
1
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1answer
201 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 ...
1
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1answer
108 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 ...
2
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0answers
39 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
39 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 $P=V^2/R$?
0
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2answers
65 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 ...
0
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1answer
91 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
267 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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1answer
97 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 $1As$ ...
6
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3answers
469 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 ...
0
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2answers
39 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 ...
0
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1answer
154 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 ...
2
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1answer
293 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
198 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
326 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
83 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 ...
0
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1answer
70 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 ...
4
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3answers
203 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
265 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 ...
-1
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3answers
178 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 ...
2
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5answers
1k views

Is voltage difference always proportional to its derivative?

We write, because of Ohm's law: $$V=RI(t),$$ but also we have $$C\frac{dV}{dt}=I(t).$$ From the first equation we deduce that $V\propto I$ and from the second $\dot V\propto I$. So we can conclude ...
0
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1answer
31 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 ...
0
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2answers
65 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
772 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 ...
0
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1answer
46 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?
1
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1answer
64 views

2 simple Generators = Im lost (intensity) [closed]

What happens? we have 2 Generators and 2 intensities, when I2 and I3 come together (they have opposite sides ) what happens? I tried writing down the voltage relations but I'm stuck because I don't ...
2
votes
4answers
340 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 ...
1
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1answer
43 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 ...
-1
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1answer
113 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
vote
2answers
83 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 ...
4
votes
2answers
663 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. ...
0
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0answers
39 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 ...
1
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1answer
597 views

The shape of the graph of the equation: $V= -r I + E$

I have recently collected data (for a school experiment) in order to measure the EMF and the internal resistance of a solar cell. The data complied with the equation: $V = -rI + E$, i.e. the voltage ...
0
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2answers
198 views

Calculating emf with and without resistance

A battery of internal resistance 2 Ohms is connected to an external resistance of 10 ohms. The current is .5 A. What is the emf of the battery? The correct answer is 6.0 V. When I calculated it like ...
1
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1answer
252 views

Voltmeter readings at different points in a circuit

I have a circuit with a 6 volt battery and 2 resistors A and B in that order.A has a potential drop of 2 volts and B has a P.D of 4 v. which means every electron moving across the resp. resistors ...