All Questions
Tagged with electricity voltage
396 questions
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How do voltage and voltage drops over a circuit relate to work done?
I have a few remaining uncertainties when it comes to voltage. I numbered the paragraphs in my thought sequence for easier reference.
In a series circuit, I know voltage is the electric potential, ...
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Questions about voltage
For some reason, I feel like the concept of voltage is escaping my grasp. I've done much research on these forums and through texts, and come across answers that seem quite well thought out, but still ...
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Capacitor related query
Why does a capacitor charge only upto the voltage of the source? I mean in an r.c. circuit if we have a resistor that is in series with the capacitor then because of the potential drop there will be ...
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Relation between voltage and current [duplicate]
What I know is that voltage is the electrical pressure which is required to drive the electrons in a circuit. According to that we have higher currents when there is a high voltage. Ohm's law confirms ...
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Voltage and current in parallel circuit
I am having a bit of a tough time understanding the following:
...
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Use kirchhoff's second law to deduce the resistance R of the resistor [closed]
Using what I learned so far, i constructed an equation like this:
$$30V=(I_{1}\times 20\Omega)+10V+(0.2A\times 10\Omega)+(I
_{3}\times 10\Omega)+(0.5A\times R)$$
Which is clearly not solvable on its ...
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Current without voltage?
Suppose you have a 120 volt, 20 amp circuit which only has a light bulb connected. When measuring the voltage going to the light bulb my meter reads 120 volts. The basics taught me that a circuit is ...
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How to evaluate, how much current flows in the circuit?
Please take into advisement, that I'm quite a beginner in subjects of physics and especially about electricity. Lately I've decided, that I want to learn more on basics of electronics and I've started ...
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Why are high voltage lines “high voltage?”
If I have two spheres of the same size and one sphere has a small amount of charge compared to the other that has a lot more charge, then clearly the sphere with the larger charge has a larger voltage ...
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Why is it written 'High voltage' in danger boards if current is the one which actually causes the shock?
After reading the answers given to this question I could understand that the amount of shock is dependent on the current and not majorly on the voltage even-though in some cases it depends.
But, in ...
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Why does voltage remains same over Parallel Circuit
Why does voltage remains same over parallel circuit. If a resistor is connected in the circuit some of the charge should be transformed into heat and make a lack of charge after the resistor (in my ...
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Why isn't this working? [closed]
I just broke a 120mm computer fan in name of science and now I'm pissed; can anyone explain why this doesn't work? :
The battery should create a potential difference across the motor, causing the fan ...
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Potentiometer voltage change
I'm trying to understand simple things about electricity reading allaboutcircuits.com web. This chapter includes image which´s principle I don't understand. Here it is:
When supplying constant ...
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Electric power for current density
The electric power produced by a current $I\in\mathbb{R}^+$ and a voltage $V\in\mathbb{R}^+$ is
$$
P = IV.
$$
Now the current is given as an (alternating) current density $J(\mathbf{x},t)=\Im(e^{i\...
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Would the empirical behavior of a simple circuit match my model of it?
I have a practical problem in E&M which has baffled me and and my electrician. The copper water pipes in my house are carrying a current of small potential (~1V) AC current. Here is my ...
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What happens when non-equal voltages are put in parallel? [duplicate]
If two batteries, say 2 volts and 5 volts, are connected in parallel, are there any problems? The higher voltage will then want to flow out, but also towards the lower 2 volt battery end, right?
user24082
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Help Understanding Non-conservative Fields
While watching a video lecture, I became uncomfortable with the results, (around 35 mins). The professor draws an electric circuit with a 1V batter, and two resistors (1 and 9 ohms). He then ...
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Volts, Amps, and Practical Electrical Knowledge [duplicate]
I've heard people say that high amperage or high voltage is dangerous to humans-aren't they both? And what are the advantages to high amperage versus high voltage? And how do you generate one or the ...
user24082
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How electrons act under rotating magnetic field?
I study Power Engineering in University. Today I asked my lecturer to explain me exactly how atom's electrons act under spinning rotor's magnetic field, that generated dynamic electricity. But he even ...
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Why is there a potential difference?
The question then asks for the potential difference between $X$ and $Y$, which is claimed to be $3.6\text{ volts}%$.
Why would there be a potential difference in this case? If I connect a lightbulb ...
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Which of these two methods is correct for calculating current?
I recently came across a question, for which I saw two possible methods of finding the solution. I was required to calculate the "current flowing" $I$ when given the voltage $V$, frequency $f$, total ...
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What kills you: Voltage or Electric current? [duplicate]
Possible Duplicate:
What causes an electric shock - Current or Voltage?
When someone gets electrocuted, what kills them; a high Voltage or a high Electric current, and why?
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How can you have a negative voltage?
How can you have a negative voltage? I don't really understand the concept of negative voltage, how can it exist?
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What does the current vs voltage graph of a halogen look like?
I have a halogen light with a tungsten filament. It is rated 500w at 130v but I am running it from an inverter in my car that is putting out 110v. I would like to know what the actual power usage of ...
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Confusion about P=VI and V=IR
If we look at $P=VI$, we see that if the current doubles then the potential difference is halved
but this doesn't seem to make sense according to $V=IR$. If we look at that equation, since the ...
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Electromotive force
EMF is defined as:
"The potential difference across the terminals of a battery or dry cell when it is giving no current to the circuit."
So, if current starts to flow from the ...
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Are square wave really square or are they always relative approximations using harmonics
I'm studying the properties of waves through different mediums, and got hung up on this.
Is a square wave always a sum of harmonics or can we produce a square wave by quickly changing voltage? Is ...
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Basic questions about voltage drop in DC circuit
I understand all the concepts of what voltage is using all the analogies but some things related to the drop of voltage across a circuit confuses me.
If I had a short circuit and attached a voltmeter ...
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What does a positive gradient on a graph of V plotted against I mean in terms of EMF and internal resistance?
According to the equation $V = E-Ir$, the gradient of a graph of $V$ against $I$ should be $-r$ (internal resistance) and the Y intercept should be the EMF. Am I right?
In an experiment I used a ...
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Why do birds sitting on electric wires not get shocked?
When we touch electric wires, we get shocked. Why don't birds sitting on electric wires not get shocked?
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Why sometimes touching old flickering tube lights starts them properly?
In my old house there are two old tube lights. Some times they don't start properly, (specially at evening time, may be it is because of low voltage), they starts flickering i.e. on and off ...
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What causes an electric shock - Current or Voltage?
Though voltage and current are two interdependent physical quantity, I would like to know what gives more "shock" to a person - Voltage or Current? In simple words, will it cause more "electric - ...
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Calculate power $P=V \times I$
I have an adapter which mentions like this...
Input: 100-240V~1.8A
50-60hZ
So how much power does it really consume?
I just knew ...
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Emf Of a Cell in a common circuit
My questions will be based on the above figure.
The Emf Source V1 and R1 Together form a cell(R1 is internal resistance)
R2 Represents the entire load on the source
VoltMeter
My teacher told us ...
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Fundamentality of voltage to current
From Ohm's Law :
Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points.
I would like to know if ...
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Why does the potential drop across a battery and resistor equal the emf of the battery?
In this diagram you can see the potential difference across the battery and resistor is the same as the pd created by the battery (the battery and resistor are representing a battery with internal ...
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How does a voltage independent current source work?
I'm having some trouble understanding what a voltage-independent current source is. How can you have a current without a voltage? As I understand it, voltage or EMF is the force that drives the ...
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is the voltage drop of a battery that is being short circuited the same as the battery's advertised voltige
So I know this is a pretty fundamental question, but I'll ask it any way. lets say you have a 12V battery, and the positive is connected to the negative directly by a wire with negligible resistance......
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How can I figure out how many kWh's are in a battery using the mAh's and voltage. [duplicate]
Possible Duplicate:
Relating milliampere-hours to watt-hours for batteries
How can I figure out how many kWh's are in a battery using the mAh's and voltage.
Some batteries only list mAh's and ...
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How do electrical devices suck electricity?
If the electric potential is 220V and some device needs 1500watts then how does it suck exactly that amount of electrical energy from outlet?
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Why doesn't an electron accelerate in a circuit?
Why don't electrons accelerate when a voltage is applied between two points in in a circuit? All the textbooks I've referred conveyed the meaning that when an electron traveled from negative potential ...
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How can AC source with different voltage provide same power?
As some of us maybe aware, USA mains connection is 110 V while those in Asian countries are 220 V. How is it still possible for the Adapter to provide the necessary power to the device, say a laptop, ...
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Neon lamp: minimal breakdown voltage
I am looking at this formula from wiki for breakdown voltage in gas discharge lamps, and I see its linear by length (d) (oops, I see it's divided by $ln$)
$$\frac{Bpd}{\mathrm{ln}\ Apd-\mathrm{ln}\ (...
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What is the difference between electric potential, electrostatic potential, potential difference (PD), voltage and electromotive force (EMF)?
This is a confused part ever since I started learning electricity. What is the difference between electric potential, electrostatic potential, potential difference (PD), voltage and electromotive ...
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When does voltage drop occur?
Why or when does it occur in a circuit? What does it imply when you speak of a voltage drop across a resistor? (Obviously, it probably means that the current's voltage before the resistor is higher ...
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Difference between current and voltage sources
I am confused about the current and voltage. My intuitive example would be that of a pipe of say water. The diameter of the pipe determines the amount of water flowing per second but the pressure is ...
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