Voltage, electric potential difference, electromotive force (emf), electric pressure or electric tension is the difference in electric potential between two points, which (in a static electric field) is defined as the work needed per unit of charge to move a test charge between the two points. In the International System of Units, the derived unit for voltage (potential difference) is named volt. In SI units, work per unit charge is expressed as joules per coulomb, where 1 volt = 1 joule (of work) per 1 coulomb (of charge). The old SI definition for volt used power and current; starting in 1990, the quantum Hall and Josephson effect were used, and recently (2019) fundamental physical constants have been introduced for the definition of all SI units and derived units. Voltage or electric potential difference is denoted symbolically by ∆V, simplified V, or U, for instance in the context of Ohm's or Kirchhoff's circuit laws.
Electric potential differences between points can be caused physically by electric charge build up or imbalance (eg. well known "static" and electronic capacitor) also by electric current through a magnetic field, and by time-varying magnetic fields (eg. dynamo or generator), or some combination of these three. Additionally on a macroscopic scale potential difference can be caused by electrochemical processes (cells and batteries) and pressure induced piezoelectric effect and heat induced emf across metal junctions. These latter processes at microscopic level have the physical origins previously mentioned. A voltmeter can be used to measure the voltage (or potential difference) between two points in a system; often a common reference potential such as the ground of the system is used as one of the points. A voltage may represent either a source of energy (electromotive force) or lost, used, or stored energy (potential drop).
If I had a turbine roughly 2 inches in diameter (4-5 blades), where the housing for the blades is about one inch wide (meaning the axle is 1"), what would be the estimated voltage I could produce if I were to use my lung power in one complete exhale through the input? That is, if there were...
5. A wire is formed into a 30 turn loop whose diameter is 14 cm and the resistance of the loop is 4 ohmns. The loop is placed on this page and a magnetic is going directly into the plane of the paper and is varying according to the formula
B(t) = 4t^3 - 9t^2 + 3t - 28
Part (a): What is the...
So, I'm asked to demonstrate the formulas for finding out the voltage labeled here as ΔU, which I'm given in my project document:
I think I would be able to make the demonstrations without any outside help, if only I knew how I'm supposed to interpret this circuit branch in the middle. Is it...
Homework Statement
Homework Equations
The voltage between any two points due to the field from a point charge q is:
Kirchoff's voltage laws, which states that the total voltage around a closed loop must be zero, i.e.:
The Attempt at a Solution
To find V(e<-d) I used Kirchoff's...
My teacher asked me to explain the reason why we need to tune the offset of the function generator of a ttl circuit to 2.5v(or -2.5v::didn't hear it clearly!) to create a shift from -2.5v to 2.5v instead of having it shift between 0v to 5v.
I've done some research regarding the high voltage and...
Homework Statement
So this was the question:
The 60W filament lamp is connected to a 6.0 V battery. The resistance of the lamp in this circuit is 70 Ohms. Explain why this value differs from the value given in (a)(iv) when the lamp is connected to the 230V supply.
My answer was:
V=IR, P=IV...
Homework Statement
Greetings.
Can someone give me hint how to solve following problem:
Homework Equations
From my understanding, you need following formula to solve problem:
and then potential can be obtained by integrating over the current distribution.
But right now these foormuas really...
Hi all
Wondering if anyone can help. Really don't know where to start
I know Zs = Ze + Z1 + Z2
and Z1 = PCR 8.9 milli-ohms/meter
and Z2 = CPC 14.5 milli-ohms/meter
which equates to 0.0234X milli-ohms/meter over X meters
but where does my volt drop come in if I don't know my current?
Regards
Homework Statement
I'm trying to understand the dependence of short circuit current and open circuit voltage on illumination.
Short-circuit current is due to the generation and collection of light-generated carriers -- so does that mean the short circuit current is linearly dependent on...
Homework Statement
FIGURE 2 shows an adjustable voltage regulator using the LT1083
.The LT1083 develops a 1.25V reference voltage between the output and the
adjust terminal. By placing a resistor R1 between these two terminals, a constant
current is caused to flow through R1 and down through...
I've been studying circuits, but I can't find any resources that really answer my specific questions. So far I understand that a battery creates a potential difference between the two terminals, one of which is positive while the other is negative. There is a buildup of positive charge on the...
Hi, i am halfway through one of my assignments and i require some assistance. I do not seek the answer to the assignment just a little boost to my knowledge.
1. Homework Statement
Basically, if i am calculating the Thevenin's voltage and the resistor i have removed that is in question has a...
Hi
I was wondering if someone could help me understand and explain to me how one can control the frequency of the grid from help of the active power (frequency -> power angle -> active power) and how reactive power can be used to control the voltage level.
My thoughts:
Voltage Control:
I don't...
Homework Statement
A circuit is arranged like above.
To make the energy absorbed by the 6 ohm resistor every second is 1.5 J, voltage X should be ... Volt
Homework Equations
V = IRThe Attempt at a Solution
[/B]
I really have no idea.
I just know that it's kinda like wheatstone bridge and...
Homework Statement
Three resistors (R1 = 3 ohm, R2 = 4 ohm, R3 = 5 ohm) is arranged like the picture above.
The voltage at point 1 is 24 Volt and the voltage at point 2 is 10 Volt.
The currents that go in R1 and R2 are 2 Amperes.
The voltage at point 3 is ... Volt
A. 10
B. 12
C. 16
D. 18
E...
In my electrical engineering textbook, in the section with voltage dividers, it says that after you combine two series resistors, then the output voltage can no longer be defined.
It then said that thus the equivalence was made strictly from a voltage source standpoint.
I do not understand why...
Homework Statement
Greetings
So i was trying to solve following prolems:
Homework EquationsThe Attempt at a Solution
I did manage to solve problem 22 using
E = NAB(2pi * f)
E = (100)(0.005)(0.9)(2pi)(50) = 141.372 v
But I have no idea what to do with problem 21. Mostly because I don't know...
Hello,
I have a bit of a problem with my project and it is as follows: I am trying to discharge a capacitor bank (2x 470uf 400V capacitors in parallel). I tried making a MOSFET switch to use that as a switch, but it kept burning out the mosfets (they were rated for 600V and around 100A), then I...
Does electrical arc with the same power but different voltage and current have same temperature?
When electrical arc is form, it is estimate that the temperature is about 3000K
Does temperature depend on voltage or current alone? Or does it depend on power(P=VA)? I think it is power, because...
Homework Statement
Determine the voltage gain Vo/Vi of the op-amp circuit
Homework Equations
inverting amplifer
vout=-(Rf/Rin) x vin
differential amplifer
vout= (R2/R1) x (vo - vin)
The Attempt at a Solution
im really struggling to even get started with this one sorry for the limited...
https://files.slack.com/files-pri/T0GNF95E2-F0TV5JSSG/voltage_reversed_and_shifted.png
This the voltage waveform across a resistor load (15W). The applied voltage is 230V AC at 50Hz. What can be inferred from this? [ the Analog to Digital conversion of Voltage happens at around 1690 Samples per...
Homework Statement
≈
What is a 3D representation of voltage using Kq/r assuming a positive point charge and what is the equation in cartesian and cylindrical form2. Relavent equations
Kq/r
3. Attempt at solution[/B]
I was trying to get a better understanding of Voltage, to really FEEL...
I'd like to find Vth by mesh current analysis.
Mesh A and B share a current source, so they're treated as one supermesh.
What's the equation for this supermesh? Also, do I ignore the loop with the open circuit? Since there's no current flowing there...
2A = ib - ia
Anyway, is this the right...
I need an urgent help. I have a 25 kva transformer in my house. Without load the volt metter indicates 114 volts. Which dould be fine for my house. But when I put the house on the transformer I have no electricity and the volt metter indicates less than 1 volt. Can anybody help me out please?
Homework Statement
[/B]
Three resistors are connected to a real battery. The open circuit voltage of the battery is 4.5 Volts. The voltage across the 5 Ohm resistor is 2.5 Volts.
A) What is the voltage across battery terminals?
B) What is the internal resistance of the battery?
Here's a...
Homework Statement
Consider the circuit shown below. a) What is the total power loss for the whole circuit? b) What is the power loss through R1? c) What is the power loss through R2? d) Find the voltage across each of the three resistors.
I didn't do this myself. I have no idea what's going...
Homework Statement
A real voltage source can be expressed as an ideal voltage source that is in series with a resistor that represents the inner resistance of the voltage source. This voltage source is a EMF and it is also in series with another resistor. Suppose both the EMF resistor...
Hi,
what are the possible reasons for selecting 11kV underground distribution system vs 22kV underground distribution system for urban area.
I know about 22kV can carry twice the load compared to 22kV.
How about impacts of pricing, fault level, stepdown from 132 kv to 22/kv etc.
Thanks
Homework Statement
The problem includes a graph. All I have is a current to external resistance graph, with 20 A coming at 10R of external resistance. I am to find the EMF and internal resistance of the battery.
Here is the problem and my two attempts.
http://1drv.ms/1LKbu5H
Homework...
Homework Statement
assume β=200,Vt=26mV,Vbe(on)=0.7V
Find the voltage gain Vo/Vs
How to find the Rth , Vs ,then find the voltage gain?
I try to draw the circuit diagram below
Homework EquationsThe Attempt at a Solution
Vth=[R2/(R1+R2)]*15
Vth=1.63V
Which method should I use to find Rth...
Homework Statement
Find the voltage gain of Vo/Vi. I'm pretty confident I have this down now, but I'd be greatful if someone could confirm I have this sussed.
Homework Equations
For the inverting op amp:
Vo= \frac{-R2}{R1}*Vi
For the differential op amp:
Vo= \frac{-R2}{R1}(V--V+)
The Attempt...
Homework Statement
Calculate the input voltage to an Op-Amp circuit. The circuit is exactly an ideal non-inverting amplifier except the inputs have been switched in that the supply is connected to the inverting input and the middle of the potential divider is connected to the non-inverting...
Hey guys, I need confirmation on this.
Since V=IR and P=IV...and V^2/R=P
Lets say your body has a resistance of 2000 ohms and you get shocked by 120 volts. You receive 7.2 watts of power.
Now let's step to the left and get shocked by 480 volts with the same 2000 ohm body.
I now get 115.2 watts...
An aircraft electrical system operates at 115 volts at 400 hertz. It is to supply an average d.c. voltage of 28 volts and an average current of 20 A at a ripple factor of 0.005.
Determine: The r.m.s. ripple voltage
Here is my attempt.
Vc= Vs-2Vd
=28-2(0.7)
= 26.6 Volts
Vr= (1/2 x fs x C...
Hi, I have built a large, lithium ion battery bank, so that I may power some of my projects from battery. The bank is 10,000 milliamp hours at 16.9 volts, and was wondering the following.
Can I charge my 16.9 volt battery pack with a 12 volt dc source? would It decrease the efficiency? Would...
To my understanding, capacitors cause the current to lead the voltage which adds VARS to the circuit and inductors cause the current to lag behind the voltage which removes VARS (in AC circuits). Also, it is my understanding that VARS increase voltage. I work for one of the largest utilities...
Homework Statement
imgur link: http://i.imgur.com/TWB5rRu.png
Homework EquationsThe Attempt at a Solution
I can find the equivalent capacitance, 10F, but I'm not really sure how to find the equiv. Thev. voltage. I figured that with the voltage source present, half the voltage will be lost...
Homework Statement
imgur link: http://i.imgur.com/zGhum8Q.png
The answer given in the back of the text is
imgur link: http://i.imgur.com/hAprWPV.png
Homework Equations
v(t) = \frac{1}{C_{eq}}\int i_s dt
The Attempt at a Solution
I get the last piece of the piece-wise v(t) to be...
We are trying to build a wind turbine which will charge a battery. Since wind speed varies (which affects the generated current and voltage), we were going to integrate a transformer in. My question is does such a transfomer even exist where the input voltage varies while the output voltage is...
I'm wanting to know if I can and if so how to measure the voltage of two AA batteries whilst they are in a device with the device turned on. This device is a vibrating toothbrush so if anyone could help with an answer, it would help teremendously with my science project as I am testing the...
If I have a certain circuit set up with a voltage V, then how does increased conductivity in the wire affect the voltage, or does it? I know that increased conductivity affects current, but if Ohm's law is to be true , voltage must increase or resistance must decrease. So which is it? Is voltage...
I have a question about relative voltages and operating points of components, in this case tubes.
Are these two functionally the same?
For a while now I never could understand how the bottom triode of the WCF in an amp I bought was biased at -100v on the grid and 0 volt on the plate which...
Homework Statement
Homework EquationsThe Attempt at a Solution
I need to know if my understanding of this circuit is correct in terms of R1, R2, Q1, Q2.
R1 is a sensing resistor and when Q1 senses a voltage drop at its base, it switches on and passes current around the regulator. I think...
Using the Delta Netowrk from this image: http://www.belden.com/images/B23_WyevsDelta.jpg
Between Y-X, there should be 120V.
Between Y-Z, there should be 120V.
Between X-Z, there should be 120V.
But wait!
If we assign values to make the above statements true...
Call X = 0V, and Y = 120V, so...