Voltage Definition and 1000 Threads

Plasma ball has a high voltage. Why don't we get an electric shock when we touch it?

Homework Statement A constant voltage source V with internal resistance r is connected to a load resistor R. The dissipated power by the resistor R is P=RV^2/(R+r)^2. Show that the maximum power dissipated by the resistor R is achieved when R = r. The maximum of P with respect to R is achieved...

A 4160v chiller motor is drawing too much power at start-up. Utility company only let's them run it once or twice a year because of it. It dims all the lights etc.. It was originally a primary reactor starter (2 contactors). The PR was replaced with an auto-xfmr and wired the same. So now it’s a...

I am struggling to understand the voltages present in the circuit below. So as stated in the diagram, there is 30V AC at the secondary of the transformer, this is equivalent of 42.4Vpeak. The bridge rectifier changes this to DC and drops the voltage down to roughly 26.3Vpeak DC where each diode...

Homework Statement Hi, so in a MOSFET amplifier question(a common-source amplifier in particular), we are examining the effects of the parasitic capacitances of the MOSFET when included in the small-signal model. In particular, the gain of the amplifier with these capacitances. So I derived the...

I am currently designing a three phase permanent magnet axial flux generator, but have a question regarding the voltage induced in the copper coils. Faraday's law defines this voltage as the number of turns in the coil, times the change in flux (external magnetic field times area of coil) over...

Homework Statement C1 = 4 micro F C2 = 8 mF R1 = 4 ohm R2 = 8 ohm V = 12 Questions : 1) Find current I when S not closed 2) find Vb, when Vc is 0 3) find Vd, when Vc is 0 4) total charge move from B to D Homework Equations Vf - Vi = F.d/q (not sure this below is useful equations) I = E/Z E...

Translated from Norwegian high-school physics book: I wonder how and why does the voltage change on the primary coil when the cookware is removed or boiled over?

Homework Statement if someone could help me with this it would be much appreciated. In physics, I used a 98Ω resistor in a series circuit and measured the current and voltage output from battery, using the current and voltage I calculated the resistance. I=0.0094A V=1 Rt=1/0.0094=106.38Ω even...

Consider the scenario Two parallel plates One ion particle (mass 1, charge +1) traveling parallel to the plates through the middle. Voltage of the plates is the same. As the ion travels between the plates the voltage on the plates ramps up, and the electric field between the plates remains...

Hi, I am currently having an issue and hope someone can help me out! I have a Digital to Synchro card on my server that will transmit the synchro signal voltage to various component. For this issue in facing, System A takes in 4 sets of data. Thus, there will be 4 sets of S1 S2 S3. At System A...

As I understand it, electrical potential is the potential energy of a unit charge in some point in space. How does this idea relate to the idea of voltage in a circuit? The term electric potential seems to be used for both.

Homework Statement I am not sure how to calculate the resistance of the circuit and each resistor using voltage and current. I know how to work the resistance out in series and parallel but am 100% how to work it out in combined. Homework Equations R=V/I, 1/Rt=1/R1+1/R2 The Attempt at a...

Hello everyone, Recently, I bought a R/C Helicopter which has a 7.4V 850mAh Lipo battery. I enjoy flying it in the field but I have a problem charging its batteries after each flight. I have no access to any car battery or 220V wall socket. I bought a Lipo charger for it which needs at least...

Good day, everyone. Let's picture a classic diagram of a voltage booster which is connected to a capacitor. If we double the capacitance, by replacing it using another capacitor with the same voltage rating as the previous one, will the circuit still be able to charge the new capacitor up to the...

Homework Statement (a) A parallel plate capacitor has area A = 1 cm2, a plate separation of d = 0.01m, and is filled with air. If the breakdown field is E0 = 3 × 106V/m, calculate the maximum voltage and charge the capacitor can hold. Homework Equations dielectric constant of air = 1 Q=CV...

So I have two formulas for calculating voltage drop. The first is: Vdrop = Vin * R1 / ( R1 + R2...). This let's me calculate the voltage drop on the first resistor in a series of 2 resistors. You can also extend this to more resistors in series just by summing all the resistors. However, I do...

Hi PF, I have a setup with two plates that are connected to two different voltages and separated by vacuum. In my case, one plate is set at -10kV, and the other plate is set at -7.5kV. I know the area of these plates, the separation of the plates (which is much smaller than the plate area), and...

[mod note: thread moved from homework forum] I have this Mouser voltage regulator https://www.mouser.com/ProductDetail/STMicroelectronics/L7912CV/?qs=sGAEpiMZZMug9GoBKXZ75xbXFDWiKqpmvrbz5I0HaKg%3D Wired according to datasheet https://www.mouser.com/ds/2/389/l79-974159.pdf see insert photo...

Homework Statement Why is my calculated total resistance of the circuit higher than the resistor used in series and the theoretical total resistance? In a series circuit I used a 100Ω resistor and measured the current at 1.0v intervals from 1.0-5.0v. At 1.0v the current was 8.70mA using a 100Ω...

Homework Statement If a Hall effect magnetic sensor is designed to operate at 40°C, how much temperature variation would be tolerable for a Hall voltage accuracy of ±5% -I have I graph of hall voltage vs the absolute temperature but I am not sure how to go about this Homework Equations...

Homework Statement All the data is on the sheet. I named the nodes V1 to V4, however I'm primarily evaluating in terms of V3 and V4. The x=V3 and y=V4 are for the systems solving I'm using. I've looked and looked at this problem, and seem to be hung up, but I suspect it is going to be on my...

hi, i tried to simulate a simple capacitor and resistor charging circuit like this i used an imaginary resistor value "10M ohm" the result as you see appear to be strange, why this happened? is capacitor's charge is relative to the voltage on the capacitor it self? and i need some...

Homework Statement For a circuit with 3 resistors in series (R1=1.00 kOhms, R2=2.50 kOhms, R3= 4.00 kOhms and Va=12.0 V). A voltmeter was placed across R2 and R3. Calculate the relative error in the voltage reading if the internal resistance of the voltmeter was a) 5000 ohms, b) 50 kOhms, C)...

So I was messing around and made a lemon battery using a zinc nail and a copper penny. I wired 4 of these lemons together and connected it to a 5mm red LED and got around 3.7V. It came on but was dim. However, when I wire my power supply and also set it to 3.7V, it is much brighter. Now i assume...

Homework Statement A charged capacitor consists of two large flat plates, one with positive charge +Q and the other negative charge -Q. An external agent trans an electron from the positive plate to the negative and also transfers a proton from the negative plate to the positive plate. There is...

Homework Statement http://www.chegg.com/homework-help/questions-and-answers/problem-2-variableh-resistor-r-circuit-fig-p224-adjusted-va-equals-60-v-find-value-r-q8083343 Homework EquationsThe Attempt at a Solution Hi, I attached a pdf file with the problem. My question is, for the lower right...

Hello All, I work in an optical lab and am currently attempting to determine the voltage output of a subtractor circuit I've wired up (as I'd like to work back from my output voltage and FFT magnitudes to read out the value of a magnetic field using faraday magnetometry.) So my circuit is as...

When does an N-ch Mosfet conduct when drain voltage varies from 0V to Vdd(like 5V). In case of Source voltage changing between 0V to 5V, all you do is check if VGS > Vth, with Vdrain fixed at 5V. But in case of Drain Voltage changing between 0V to 5V, how does it work?

Homework Statement What is the relationship of charge polarity and voltage polarity? I understand an anion has negative charge and cation ion has negative charge, but does an anion have a positive voltage and the cation have a negative voltage? Given the above is generally true, when is the...

Hi PF! Though I've lurked here for some time, this is the first time I've created an account. I'm a volunteer in a country in West Africa. The school I teach at has a tiny library with 4 small dell PC's and a printer that were donated some time ago. A grant was used years ago to buy a battery...

I am trying to build a Voltage Doubler to use a motorcycle 6 Volt a.c. alternator's dedicated headlight coil (which presently runs a 36W incandescent headlight bulb) to provide 12 Volt d.c. to drive a commercially-bought 12V LED headlight unit (also rated at 36W). Frequency will be (1500 ~ 5000...

Homework Statement Theses questions have been modified to solve my own inquiries. The originals can be found in the attached file. A parallel plate capacitor has area A = 1 cm2, a plate separation of d = 0.01m, and is filled with air.(a) If the breakdown field is E0 = 3 × 106V/m, calculate...

Homework Statement Consider the circuit How long after the switch is closed does the voltage across the resistor drop to Vf = 20V. Answer in units of s. Homework Equations Tc = RC Q=Qm(1-e-t/RC) The Attempt at a Solution [/B] RC = .0003026 11 = 31(1-e-t/RC) .3548 = 1-e-t/RC 1.3548 =...

I need help regarding piezolectric effect... If I add DC voltage to piezoelectric crystal it will change its dimension (length) and vice versa: if I put pressure on piezoelectric crystal it willl produce DC voltage on its surfaces... But I am wondering how long this voltage will last? If I keep...

Hello Everyone, I am still trying to get my head around what a current to voltage converter (and vice versa) is. There is a section on my book, in the chapter about op amps, that discusses this topic. Apparently, a current signal is less susceptible to noise than a voltage signal... But what...

I'm trying to understand what exactly it means in terms of the voltage of a battery. I know that the voltage in a battery is just the potential difference between the two terminals. But, is the negative terminal used as a relative point and seen as 0? If that's the case does 12V mean that the...

Hi, did you ever get to understand why a fuse installed in the Hot (Live) conductor of a circuit doesn't rupture when the AC Polarity reverses with the Neutral conductor bonded to Ground ? I still don't get it i.e. if current flows in both directions then the polarity is allowing the Hot wire...

Homework Statement Q1: A power plant produces energy at a voltage of Vi = 18667 V. Before being sent along long distance power lines this electricity is sent through a transformer with 143 turns in the primary coil and 8971 turns in the secondary coil. Voltage is calculated to be...

Homework Statement Homework Equations V = IR And R becomes 2(r of one conductor) because of return path. The Attempt at a Solution V minimum is at third junction. At VD Using KVL we get: [/B] Drop at AB = (10 + 20 + 50) * 2 * 0.1 = 16 V Drop at BC = (20 + 50) * 2 * 0.08 = 11.2 Drop at CD =...

Homework Statement Given the known quantities ##R, C, L##, ##k##, and the effective values of the voltages ##E_1=E_2=E_3=E## , ##w = \frac{1}{\sqrt{LC}}## of the direct-symmetrical 3-Phase system find the expressions for the effective values of ##U_{12}##, ##U## and ##I## and calculate the...

My question is whether voltage is actually a magnetic force that pushes electrons through the electrical circuit. My question arises from the fact that conductor passes through the magnetic field and if the circuit is closed we have the electron movement as some force pushes the electrons it...

I read online that insulation rating of the conductor depends on the voltage rating and not on the current. Can some one explain me how current doesn't contribute to insulation rating? Am i missing something? Kindly explain me

Homework Statement A solid sphere with radius R=12 m has charge Q=3 nC distributed uniformly throughout its volume. (a) Calculate the potential difference between a location at infinity and a location on the sphere’s surface. (b) Calculate the potential difference between a location on the...

Homework Statement For AC Circuit shown in the picture, ##C=60nF##, ##L=100uH##, ##X_3=-100Ω##, ##Z_2=50Ω## and ##Φ_2=\frac {\pi}{6}##. When the switch is closed the ammeter shows a current ##I_1=0.6A## and the voltmeter shows ##U_l=60V##. The measuring instruments mentioned are ideal...

Homework Statement Homework Equations I drew phasors and got the answer. Angle between V and I is 60 degrees. Cosine of 60 is 0.5. Then I multiplied V and I and divided it by 2.The Attempt at a Solution I got answer 62.5. But I'm not sure if values of V and I given are rms values or maximum...

Does potential difference only indicate how much energy each coulomb have, or make current flow, or do both?

With ground where it is, how does current travel the rest of the circuit? I thought that as soon as current met ground it was gone

I have wired in series: + of 9V battery --- + of 1000 uF capacitor --- 660 Ohm resistor --- + of a green LED --- - of the 9V battery. Remark: the 9V battery is a bit depleted 7.8 V unconnected. Voltage drop across the capactor is 6.5V, across the LED is 1.5V but 0V across the resistor. Why...

Homework Statement Homework EquationsThe Attempt at a Solution This is a solved example given in my Physics textbook . I am not understanding a couple of things . 1) How is Iin calculated as Vin/Rin ? Why is the book not taking potential difference between Base Emitter into consideration...