Ac Definition and 1000 Threads

I am trying to understand this curve; it is AC Power vs. Field Current of a DC Generator. I am not sure what its significance is? What it's telling me? Can someone please explain it to me? See attached image. BTW... Pac = AC Power If = field current Poc = open circuit...

I khow water conducts DC electricity but AC ?

Hi at all, I need to convert a DC signal ranging from -2 V to +2V to a AC signal with an amplitude of approximately the same voltage at let's say 1 MHz. The frequency can vary but has be higher than 10 kHz. I looked for PSW inverters but didn't found any suitable. Our intention is to record a...

Homework Statement Hi I have been told that the question below might be similar to potential university interview questions for physics/electronic engineering. In relation to this circuit diagram: http://forum.allaboutcircuits.com/attachments/diagram-ac-diode-capacitor-pd-question-png.90713/...

Homework Statement Homework EquationsThe Attempt at a Solution I am surprised that this question came up, I haven't learned ac circuits yet. I don't know how to solve this. I just added both values and current and divide it by two, which gives me 1.5A, since I thought it's the average but I'm...

Does anyone of a transformer that can step up 120vac to 460vac? Or do I need to use two transformers and step it up twice? It is powering a 10hp 460vac 3phase ac motor. Thanks.

how do the appliances work with AC voltage when the polarity keeps changing?

Hi Everyone, I have 4 scenarios in question . Will The EMF(Voltage) be the same in all of the scenarios? - the difference between the two photos are the polls: one repel one attract . - i understand that the current(amps) will change due to the wire length assuming same gauge 1) Photo...

Homework Statement A series RLC circuit is connected to a 60 Hz AC source which produces an amplitude of εmax=20 V. The circuit element values are R= 20 Ω, L= 20 mH, C= 150 μF. Calculate the total impedance of the circuit. Homework Equations Xc=1/ωC XL=ωL Z=√(R^2 +(XL-Xc)^2) tan φ = (XL-Xc)/R...

AC is varying.So why does the brightness not vary?

Hello, I want to know determining the number of poles by inspecting coils inside the motor. Generally, there are formulas allowing us to plug a frequency, an rpm, and give off the number of poles, or we can just simply look at its nameplate. My reason for needing the inspecting is that my...

Here is my misunderstanding , for the example let's ignore resistance losses , say i have a infinite length of coil , and an infinite strip of magnets passing through that coil, each magnet separated by some distance from the next one , the strip of magnets move through the middle of the coil ...

I have been studying capacitors and inductors recently and I have seen this video. I have a few questions about capacitors and inductors. Capacitors: 1.how do capacitors discharge? 2. What happens when you apply direct current through a capacitor? 3.Do capacitors only allow certain...

Hello. I need to confess that I'm noob for electronics and studying right now. I'm in OP-AMP study and found some sentence which is hardly understood for me. "If the signal source is ac-coupled, you must provide a return to ground for the (very small) input current, as in Figure 4.6." (Please...

Hello. I've recently have a lot of question of building Faraday cage for our high voltage gas discharge lab. I think this question is a kind of fundamental question for such a job. Let's say I would make perfect Faraday cage with perfect shielding or have metal plate of infinity transverse...

I'm a bit confused as to how only one wire changes it's polarity in an alternating circuit. I also checked out a previous thread (https://www.physicsforums.com/threads/how-can-polarity-of-ac-inverse-but-keep-the-live-hot-and-neutral-cold.752605/) and didn't find a sufficient answer. I found this...

my electric supply company some time supply very low voltage which cause damage/burn out my Tv three time do you know any sort of device which disconnect power supply to my Tv and my Tv un harm from low voltage my electric company uses 220 volt supply or british system. please help me

Homework Statement The following coil-wound core (core length = L , Gap length = lg, cross- sectional area = A , core permeability = only hysteresis graph is given, N = N turns) is driven by a Voltage source, is known that the current in the coil is 60hz AC. Determine...

Hi everybody, As part of my research at UCSD, we are trying to measure Hall resistance of some materials. And to do that we need to send an AC current. So I wondered how we could easily build an ac current source, probably based on op-amp. I know there is the Howland circuit (current pump), but...

Can we use same refrigerant for both air conditioner and refrigerator?

Homework Statement Given a series RLC circuit, with one R, one L, and one C element, and an AC voltage source with variable frequency, find the resonant frequency experimentally given an ammeter and a voltmeter. Homework Equations The current in the circuit when the circuit is in resonance is...

It is my general understanding that according to KCL, current requires a closed loop to flow in DC. However, this is apparently not true in AC; current doesn't needa closed loop to flow. I have drawn a circuit below which causes confusion: C1 is a charge capacitor, R1 is a resistor, I1 an...

If drift velocity of electrons changes in AC, how does electricity flow through a circuit to then lose potential energy to the devices in the circuit? Also considering the change in direction, does that mean that the live wire and neutral wire also switch roles in AC mains? I am very confused...

Hello, I remember a few decades ago I built a circuit with my dad using what I think was a 741 op amp and a 555 timer and a loose wire. When you'd touch the wire, an LED would light. Then it took 30 seconds for the circuit to reset. I remember he said it was called a [logic] gate. Present...

I know 2 simple ways to convert AC into DC: Wheatestone bridge with diode is one the other is increasing the number of loops in magnetic field in DC power generation. Is there a simple way to convert DC into AC? I suppose a motor could spin a loop of wire without a commutator in a magnetic...

Homework Statement Here is the circuit. I have to solve for V Thevenin I am having trouble figuring out what I am doing wrong here. I need to solve for Vth and I do, but it does not match with what my TA posted as the solution. [/B] Homework Equations The equations I set up are the same as...

Hello, I'm currently working on a problem involving the calculation of an unknown voltage source of a circuit containing a resistor, inductor and load in series. Unfortunately, the problem sheet does not give an answer at the end, so I am unsure as to whether my approach is correct -- hence...

Homework Statement The circuit in operates at 60 Hz with Emax = 170 V, and R = 4.5Ω . How much energy is dissipated in the resistor in 0.75 s? Homework Equations P = VI For a circuit like mine with only a power source and resistor, the current and voltage are in phase, so V = E max sin (ωt)...

Homework Statement Homework Equations phasor forms voltage division current division The Attempt at a Solution Using superposition, considering only the varying voltage source. Z (L) = 4j Z (C) = 5j Total impedance: 4 is parallel with 5 = 2.44 + 1.95j series with 1 + 4j Total...

From textbook: "In much of the world (Europe, Australia, Asia) the rms voltage is 240 V, so the peak voltage is 340 V. The line voltage can vary, depending on the total load; the frequency of 60 Hz or 50 Hz, however, remains extremely steady" Why is it so important to keep it steady? what...

Homework Statement How large an inductance should be connected in series with a 120 volt (rms), 60 watt light bulb if it is to operate normally when the combination is connected across a 240 volt, 60 Hz line? (First determine the inductive reactance required. You may neglect the resistance of...

Hi. I'm joining this forum to ask about some equipment I need. At the community college where I teach, we do a lab in freshman physics where students measure the input to and output from a transformer. My AC sources are reaching the end of their lives, so I'm looking for replacements. As far...

Homework Statement Determine using nodal analysis the current in branch Z4 Homework Equations [/B]The Attempt at a Solution [/B] Not sure how to handle the source v3 my solution so far has came up with answers that are not the same as the answers that I got for mesh analysis. Node A...

Hello, I have forgotten most of the electricity physics we studied and I have problem describing/understanding a concept. Does AC current produce less loss than a DC current? I found this statement in a website: "AC electricity loses less power over power lines than DC"...

It is a cylindrical ac machine. If we want to produce a sinusoidal voltage, we need B (magnetic density) to vary sinusoidally. To get B vary sinusoidally, we need to get H(magnetic intensity) to vary sinusoidally. To get H vary sinusoidal, the best way is to vary the numbers in the air gap...

Homework Statement Homework Equations KVL at that loop The Attempt at a Solution I can easily solve all the individual current and voltages in this circuit using Mesh analysis and Gaussian Elimination. But how do I get Vx? I can simply add the voltages of the two 10uF capacitors if they are...

If you buy a generator (gas powered etc) there is only a certain amount of watts that the generator can put out. This is because the engine only has a certain power rating (and losses). However, if one were to put a higher power engine on the generator head and remove the safety breaker for...

Thanks

Many modern electric train locomotives have the option of regenerative braking. Most of these locos have HVAC power transmission. I'm wondering, when they brake in regenerative mode do they actually generate DC (I'm not sure whether modern electric locos prefer DC motors or AC motors or is the...

Homework Statement Need to find Voltage V. I know that I need to first solve for the currents, have tried using loop rules, not having much luck. Homework Equations Just would like to know how to approach, and solve, this problem. ME and circuits has never been my friend, thanks! The...

Can I say that energy transmitted in DC by electrons flow like ants walking align and in AC by electron vibration like water wave ?

Homework Statement The rigid bar AC is supported by two axial bars (1) and (2). Both axial bars are made of bronze [E = 100 GPa; α = 18 × 10−6 mm/mm/°C]. The cross-sectional area of bar (1) is A1= 211 mm2 and the cross-sectional area of bar (2) is A2 = 303 mm2. After load P has been applied and...

Homework Statement I m not able to understand one of the methods to reduce error in measurement using ac bridges. "All the leads to a single corner should be brought as nearly as possible to the same point" Homework Equations I am providing the bridge layout image and a,b,c,d are corners of...

Homework Statement I have given the T - bridged network figure and I have to calculate unknown inductance and resistance? Homework Equations I solved a lot of bridge problems using balanced bridge equation :- (Z1)(Z4) = (Z2)(Z3) But I have no idea how to proceed in this question , please...

What is the highest possible AC frequency being able to be generated. I don't care if this is usable in a circuit but as long as it can be physically made, what is the highest AC frequency possible? I've heard 70GHz was the max using an amplifier.

Why do we use the square of the graph as opposed to the absolute value of the graph to find the mean values?

First off, I am sorry this post doesn't match the template guideline. I didnt realize that it was mandatory until I went to post this. I tried resetting it to get the template back, but it just restores my post. I am not understanding this topic whatsoever. We used an oscilloscope to measure...

Hi everyone,1. Homework Statement Three inductors with 0.1 H each are delta connected to three phase ac newtork with 220V/50Hz. Determine Iph, IL, P, Q and Theta. Homework Equations Showed at the attempt. The Attempt at a Solution [/B] XL=2*pi*f*L=31.4 ohms Iph=Uph/XL=220/31.4=7 A...

I wonder if AC current follows Sin wave and go through negative and positive cycles alternately, why don't AC equipments, like a bulb, get off and on - off and on...

I simply wanted to know, whether we can store AC power like DC?