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

learn more… | top users | synonyms

0
votes
1answer
39 views

What happens if I have a square conducting wire being permeated by a magnetic field and the field suddenly disappears?

Suppose there is a square conducting wire in a magnetic field. The two vertical branches will have the same emf, and the two horizontal branches will have 0 emf, resulting in a net emf of zero and ...
0
votes
1answer
32 views

Can electromagnets repel?

So I saw a video here https://www.youtube.com/watch?v=wzXRFp0DDrU (See the full video first) I don't understand that how is the electromagnet repelling things in the second half of the video? Also ...
0
votes
2answers
38 views

Is this diagram in my textbook not constructed to scale?

Or am I having an illusion. Clearly, the distance from 6v to 4v is not the same as 4v to 2v. I know it should be based on: $V = k\frac{q}{r}$.
0
votes
4answers
108 views

How power lines use high voltages with a low current?

I've read that power lines use high voltages and low currents to reduce power loss due to resistance. Looking at the formula for power - P = VI So to increase P, you increase V rather than I for ...
8
votes
5answers
3k views

How can one derive the Ohm's Law?

I am looking for the derivation of the Ohm's Law i.e., V is directly proportional to I. Can someone help me with it?
0
votes
2answers
131 views

Induced EMF, additive to conductor's closed circuit?

Assume the following conductor, with current flowing, powered from a source $S$: Now, I've introduced a magnetic field($B) to the conductor covering a small area of it like so: The change in ...
0
votes
0answers
9 views

Reasons for a voltage follower introducing voltage gain? [migrated]

Im using a 3130 op amp as a voltage follower (unity gain buffer amplifier). However it is introducing voltage gain. It is wired the following way: This is then just fed into a simple low pass RC ...
0
votes
1answer
38 views

Grounding a capacitor

When one of the plates of an isolated capacitor is grounded, does the charge become zero on that plate or just the charge on the outer surface become zero?
2
votes
3answers
49 views

Why is resistance across a load the V per I rather than the V per Q?

There is a load that resists the flow of electrons. This causes a voltage drop, meaning it creates a potential difference between the 2 sides of itself. This property, a load creating a voltage drop, ...
0
votes
1answer
24 views

Is internal resistance relevant in motional EMF?

When a conductor passes a magnetic field and connected to a circuit, the induced voltage is calculated via the motional EMF($\epsilon$): $$\epsilon=-vBL$$ Is the conductor's resistance (or internal ...
0
votes
0answers
19 views

How to calibrate an ammeter and voltmeter? [migrated]

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?
0
votes
2answers
51 views

Why is voltage essential in circuits?

I understand what voltage is, but why is it necessary for an electric circuit to function? Why can't current flow without a voltage?
0
votes
1answer
38 views

Reducing eddy currents, changes the property of the conductor & circuit?

In an attempt of reducing the eddy currents in a conductor, such as having gaps to break the induced eddy currents, would that by any chance change the conductor's orientation from series to parallel? ...
0
votes
1answer
27 views

Does the power of the resistor change when the battery is changed?

Wanted to know whether the changing of a battery (potential difference)affects the change of power consumption of a resistor of a bulb. please tell me how the change will occur?
2
votes
2answers
70 views

Why does voltage change in series circuit but not in parallel circuit?

Voltage divides after every resistor in series but not when placed in parallel. Please explain this with using very less or no mathematical equations. I have tried searching for an answer online but ...
0
votes
2answers
49 views

Which is more important, current or potential difference?

If i have a bulb rated 4V, 4A, and my power source is 2V, 2A. Should I use a step up or step down transformer to make it 4V, 1A or 1V, 4A? Which wold make it glow brighter?
1
vote
1answer
44 views

How do domestic appliances work at different voltages when the applied voltage is same for every appliance?

Generally, the electric connections at home are in parallel combination. How is it possible for a geyser(220 Volts) and a cellphone charger (5 volts) to operate at different voltages in a parallel ...
1
vote
1answer
19 views

How does static protection really work?

I've read that while working with circuits you want your body to stay at the same voltage as the components you are trying to protect. So you're supposed to connect those wrist things to one of the ...
0
votes
3answers
73 views

What is the voltage at every pair of points along a ideal wire that is connecting the two terminals of a battery?

If you stick a wire across a battery, obviously it is going to discharge the battery. This will be due to a voltage difference between the two terminals. However, the equation $V = IR$ tells you how ...
1
vote
0answers
15 views

Is their a visual difference between air-gap sparks of the same voltage but different current?

For example, if this spark gap has a kilovolt of power behind it @ 1A and the other is also at a kilovolt but is @2A will there be a visual difference (i.e. will the one with higher current be ...
0
votes
0answers
23 views

Is it possible to raise the voltage of a power source by lowering its current indefinitely (i.e. transformers)?

Let's say you have a D battery. You wire it up to the primary of a step-up transformer, which you then in turn wire up to another step-up transformer,...etc. Is there a limit to how high the voltage ...
1
vote
1answer
61 views

Is my understanding of electric fields accurate?

Could someone please help me and let me know if the statements below are any accurate? I am struggling trying to understand what electric fields are and I could really use some help! An electric ...
4
votes
1answer
265 views

What creates voltage?

I was trying to break down how a transistor works to a friend, and I took a moment to think about electric current and voltages. I realised I do not understand where these phenomena come from. I ...
0
votes
0answers
66 views

Electric potential difference

From what I have read, since electrical potential is essentially EPE/unit of charge, it would be position dependent (relative to the electric field). Electrical potential difference is then defined ...
1
vote
3answers
66 views

What does it mean when we say that power of a bulb is 10 W? Since $V/I=$ resistance is a constant, how can power $=VI$ be a constant?

My question is simple. In Ideal situation, at constant temperature, we know that normal appliances like a filament bulb has straight Voltage vs Current graph, meaning its resistance is constant or ...
0
votes
1answer
102 views

Resistance & temperature of semiconductor

From what I have read about semiconductors, the reason their IV characteristic shows a decrease in resistance is because as voltage is increased, current is increased. However, the reason for the ...
0
votes
2answers
108 views

How is a potential difference created between two points?

I would like to know how potential difference is created between two points?Is potential difference created by adding more electrons at one side?If that's the case how to add more electrons at one ...
0
votes
2answers
60 views

Is it low current or low voltage that dims a bulb?

At times we have dim bulbs due to some fault from national grid, what I want to know is if this fault is low current or low voltage. Other times electrical appliances blow-up, is that high current or ...
1
vote
2answers
120 views

If induced voltage (back-emf) is equal and opposite to applied voltage, what drives the current?

Suppose we have a circuit with a voltage source, a switch open and an inductor all in series. If we close the switch, the potential difference of the voltage source is instantaneously applied to the ...
0
votes
1answer
67 views

Confusion with potential difference [closed]

I was trying to solve a hard problem involving a circuit like this: Find the reading on the voltmeter (red ones are resistors) I don't know how to think about potential difference across branches ...
0
votes
0answers
40 views

How to apply voltage source in FEM when solve Maxwell equation?

I need to solve the Maxwell equation of electric field by finite element method. In this function, the right hand side is the current density. However, in my problem, the voltage source with 1 MHz ...
1
vote
1answer
70 views

Filament lamp: Negative part of I/V characteristic?

I don't understand the negative part of the graph. It shows that the resistance is decreasing as the voltage goes from negative towards 0. What does a negative voltage mean and why does the graph ...
1
vote
1answer
54 views

Filament lamp gets hot, metallic conductor doesn't?

Keeping the temperature constant, if you increase the voltage across a filament lamp and a metallic conductor, the filament lamp gets hot but the metallic conductor doesn't. Both are made of metal so ...
1
vote
2answers
69 views

Voltmeter in series with a component?

I always see voltmeters connected in parallel with a component, but what happens if you connect it in series? I think it's due to the high resistance of a voltmeter but I don't really see why this ...
0
votes
1answer
66 views

Efficiency of an electric motor? [closed]

Question: An electric motor runs off a 12V d.v. supply and has an overall efficiency of 75%. Calculate how much electric charge will pass through the motor when it does 90J of work. Can someone tell ...
1
vote
1answer
43 views

Capacitors and Voltage

Imagine if I have a capacitor, connected to a battery of $12 V$. After charging the capacitor, I increase the plate separation. Then my capacitance decreases, right? But charge should be ...
1
vote
2answers
74 views

Does sending current upwards reduce the voltage?

I was thinking about relativistic situation of having a vertical wire on a neutron star or high-gravity environment and then say if I send current upwards (away from the ground) will the voltage be ...
0
votes
1answer
20 views

Current function of voltage, Taylor series

Why can the current as a function of voltage for any device be written as a taylor series? Is it because voltage can be written as V0 Cos wt and then I = V/R ? I'm confused on this.
1
vote
3answers
62 views

Why is the zero of electric potential taken to be $r = \infty$, rather than $r = 0?$

Wouldn't it make more sense if it was taken to be zero at $r = 0$? This seems to imply that with a negative test charge at $r = 0$ from a positive point charge, $V = -\infty$, which I have trouble ...
0
votes
0answers
20 views

Is the induced EMF dependent on the conventional or actual flow of electrons?

I have been studying Faraday's Law and Lenz's Law and the flow of current to oppose change in flux linkage. My question is whether the actual flow of electrons to the top of a material makes the EMF ...
0
votes
1answer
45 views

Energy, Voltage Drop, and Current

In an electrical circuit consisting of just a source and some load, when current hits the load, the voltage drops. This means that the potential energy of the charge drops. If the potential energy ...
2
votes
2answers
85 views

What is the voltage of an average carpet static shock? Can you make it lethal?

I think I heard somewhere that it was in the thousands of volts, but it had extremely, extremely low amps. Could you somehow transform the current to make it larger or something? Or does the equation ...
1
vote
1answer
207 views

What determines the forward voltage drop for a diode?

I have always had the idea that the forward voltage drop in a semiconductor diode was related in a simple way to the bandgap energies in the semiconductor. However this is apparently not the case: ...
1
vote
2answers
26 views

How do I choose the right value of $r$ to find where the electric field is zero?

Sorry for the long question. I'm having a difficult time trying to explain my confusion. I have a positive point charge$\ Q_1 =+q$ at the origin and a negative point charge $\ Q_2 = -2q$ at $\ x=2$ ...
0
votes
3answers
72 views

How does the voltage across an inductor and a capacitor vary in series LCR circuit about resonance?

I am aware that at resonance, the voltage across the inductor and the capacitor are equal in magnitude and opposite in phase. However, I want to know how the voltage across $L$ and $C$ vary if I vary ...
0
votes
1answer
20 views

What is bias voltage and what is it's function in a Scan Tunneling Microscope?

I was reading about the Scan Tunneling Microscope and I read that a 'bias voltage' is needed to realize a current of electrons between the needle and the sample. I don't know what the definition of ...
0
votes
0answers
24 views

Induced-EMF in a parallel circuit, vs a series circuit?

I wanted to know the difference between the induced-EMF in a series circuit layout, vs a parallel circuit layout. In a series the current would stay the same,however, the induced-EMF would increase? ...
0
votes
1answer
38 views

Current and Resistance-Effects of the Length of the Wire

Two wires of the same material are both connected to a 9-V ideal battery. They have the same cross section area but wire 2 is twice longer than wire 1. Compare the following quantities by answering ...
0
votes
2answers
89 views

Why does a voltmeter give a positive reading for a path in the same direction as the electric field?

Straight from my textbook: If the direction of the path from initial location to final location is the same as the direction of the electric field, the potential difference is negative. Yet a ...
-1
votes
1answer
57 views

How to find the voltage?

How to find the voltage ? Given is the following mixed circuit below, every resistor has the value $1$ ohm, the current flow through the last resistor is $1$A and I have to find the voltage V ...