Ac Definition and 1000 Threads

When I put a current into a dc motor, there will be a turning effect. But I thought as this happens, won't there the an induced current that flows in the opposite direction? Bt Fleming's Right hand rule, the current will flow in the other direction. So I'm quite confused about this...

Hello! I'm a long time reader, but this is the first time I've not been able to find the information I've needed already... I have a small electromagnet that needs to have an AC current (it is essential that the electromagnet has a reversing polarity) but the source of power comes from a 6v...

Hi, I'm comparing two electrical appliances, one with a DC motor and the other with an AC motor. The AC appliance has 250 watts. The DC appliance has 0.6 amps and 120 volts, and its wattage is 72. Given these specs, I would like to know which appliance would have a more powerful motor? In...

Hi, I have a central vacuum system that has blown it's circuit board up. Basically a hoover with a low voltage switching system to fire the motors up. Finding a new board will be difficult so I'm going to rebuild the control system. I can solder, can rewire a house, but the finer points of...

Hi all, I have a question with regards to why should we use an ac-dc, dc -dc, dc-ac converter to an ac drive? Why not connect an ac source through a transformer directly to the ac drive? Isn't it the same? What equations can prove that the use of converter is a better choice?

This is from wikipedia's article about Variable-Frequency Drive Controller: Variable frequency drive controllers are solid state electronic power conversion devices. The usual design first converts AC input power to DC intermediate power using a rectifier or converter bridge. The rectifier...

"why are inductors preferred over resistors in reducing current in an AC circuit?" The quoted question from a recent exam has caused a little dilemma regarding it's interpretation and answer. 1) what does 'reduce' refer to? 2) inductors are preferred as the impedence is dependent on the...

Hi everyone! First post on this really awesome forum! I'm thinking of an AC-adapter for hot-shoe flashes, which are usually powered with batteries. Here a guy describes his unsuccessful attempt: he built a wooden battery pack with contacts at the right place and connected to a universal...

Hi people. I started my AC circuits course in college, but this stuff is either too tough or I probably don't have some math prerequisites. By the way, I'm just starting my differential equations course, but I haven't had any time to study just because AC circuits won't let me make any...

AC coupling using NMOS Hello. What does AC coupling by using NMOS and PMOS actually means?

I am on a Formula Student team and we have decided to design our own brushless AC motor. Our main issue is how we will cool the motor, since we want to keep weight down while also increasing power output. We will be making the rotor from forged Titanium (Ti6Al4V) and the housing from forged...

I have taken apart a speaker set which uses a transformer to transform the 230-240v mains it receives into 9v AC 1A. I want to connect this circuit to a 9v battery. Nothing complicated-the standard Duracell one. Does anyone have any advice/comments on whether this will work or not? Regards...

Is this even possible? Since light is an electromagnetic wave, creating an alternating current will create fluctuations of electric and magnetic field and will... make light? I highly doubt this is possible, but I thought it was worth asking to see why it CAN'T happen.

how to find power factor of the load, the three voltmeter readings are V1=220v,V2=122v,V3=136v

Hey all. I have an old garage door opener motor. Its a 1/3 HP, 1000 RPM, 115 volt, 3.6 amp, AC Motor (Am I correct in thinking its single phase?). I'm attempting to motorize a grain mill that I have in the kitchen. (the faster I can grind the wheat the faster my wife can make homemade bread...

What happens? I think nothing should happen since the rods will not get magnetised at all due to the ac current.. Thanks for the help!

when you place a magnet into a solenoid with a ac current it will get demagnetised. So does this mean that the magnetic field will go into the magnet in the opposite direction of the magnet's own magnetic field? and disalign it. meaning will the magnetic field enter the magnet as though it is...

Hello all! First post! I've built a 7.83 Hertz sine wave oscillator that is fed into a 1,000 wind coil (soft iron rod/bifilar windings/self cancelling) and have tested in out on my oscilliscope and it's working beautifully with a peak voltage of 5.8 VAC (4.1 RMS AC). This device is being...

hi i was wondering if we would treat inductors and capacitors as short circuits for AC voltages. i am aware that there is a 90 degrees phase shift in a RC or RL circuit with an ac voltage but the phase shift only applies to the current. thanks

Homework Statement Basically we were given the attached picture and we are supposed to find at what value for the AC frequency from the Vin will the amplitude be halved at V (CE base) Homework Equations The Attempt at a Solution I think i am supposed to use V=Iz where Z is the...

What are the merits and demerits of 50 Hz and 60 Hz AC system? Which one is better?

Hello community. I am currently working on a product that requires relatively high torque and rpm, around 3 N/m torque and between 150-300 rpm to be specific. My knowledge about motor is very limited and i am running out of time. I understand that i won't find the exact spec and probably will...

The voltage is large AC signal, not small AC. I never deal with this kind of biasing... I am doing some simulations to extract the impedance of the device. I heard about some ways to measure it, like load pull, S parameter. But I can't not do measurement now... The device is quit...

Homework Statement There is this experiment regarding the frequency of AC mains using a sonometer and I found a slight confusion with the formula. there is an electromagnet attached to a step down transformer and a wire is placed below the electromagnet, and by varying the length and tension...

Hi, I am currently struggling with this AC question that is required for my first year electrical engineering coursework. I know sort of how to go about it all, but am having a really difficult time implementing the correct calculations. Any help would be appreciated! Context You are given a...

Hi, i wanted to control one of my home appliances basically to switch it off after some time (as of now 10mins). i got stuck up at the first step itself where i want to know whether the switch is ON i.e. i wanted to detect whether AC input is on. So my basic question is how to detect a 230v...

Can someone explain how the Stark Effect works in Layman's terms? I'm trying to understand how an electric field can cool down atoms. What is the electric field doing exactly to the atoms? How is it lowering the atomic energy levels? Is there a difference between Stark Shifting and Stark...

I'm working on an ac circuit, and we were told to use nodal analysis. Furthermore, we are asked to show a power balance between the sources and the power dissipated in the resistors, along with a reactive power balance between the sources and the inductors and capacitors. I have this formula...

Hey guys, I'm attempting to use this chip, http://www.national.com/pf/LM/LMD18200.html#Diagrams with a simple 555 circuit as the input to drive an AC signal out. From my understanding I can have the 555 going into the PWM input, a relatively high current connection to Vs, this will then...

Voltage V(t)=V1 Re{eiwt} produces a current I(t)=I1 Re{e(iwt+θ). Determine I1 and θ. The circuit is AC so do I treat it the same as an SHM question? Is π/2? And what do I need to do to find I1? I don't know where to start.

For the circuit given in the power factor is 0.72 lagging and the power dissipated is 375 W. Determine the: (1) apparent power (2) reactive power (3) the magnitude of the current flowing in the circuit (4) the value of the impedance Z and state whether circuit is inductive or...

Could somebody to explain me, please, how works revers system on the one phase AC synchronous motor with two wires only. Model is 50TYZ-E and it is from small ice making machine. Where does this motor get information, that now is time to turn opposite way? Thanks in advance! Veiko

Homework Statement In the circuit attached the load impedance ZL comprises a resistor in parallel with a capacitor. Determine the value of the resistor and the capacitor to ensure that the maximum power is received by the load impedance. The Attempt at a Solution So,if components in ZL...

how frequency play vital role in AC?? AC has certain frequency set for it., in India 50hz and in America 60hz is kept as standard frequency.., y is that kept so?? is it possible to keep frequency value higher than this??

Hello everyone I am trying to make a small three phase ac stator so a rotating magnetic field will be produced. I can use a ring with an outer diameter of 3 inches and an inner diameter of 1.5 inches with each of the six poles being 1 inch with about 100 turns of 24 magnet wire or a ring with...

Why DC is said to be more dangerous than AC?? For example, consider a 230V DC and 230V AC.., it is said DC voltage is highly dangerous than AC.., Why is it said so?? how much quantity of AC and DC can our body bear and remain harmless??:confused:

Hi all, An electrolytic capacitor has 2 AC sources connected to it, 1 at each plate. The AC sources are 180 degrees out of phase and have a high impedance which limits current in the nA range. Even though each plate should have AC on it which is 180 out of phase the voltage at each plate...

how to design dc to ac inverter

Say I have an AC motor with 100 ft*lbs torque, and I run it against a load of 200 ft*lbs torque so that the motor spins in the opposite direction of the power it is providing. Is this possible, and if so can this condition be sustained over a period of time without damaging the motor?

I just bout some wireless controlled wireless outlets. Theses are what I bought: http://www.menards.com/main/electrical/safety-security/timers/indoor-wireless-remote-outlets-3-pack/p-1477247.htm I want change how they draw power and the functionality. I am new to circuits and have a novice...

What should be value of PTC/ Resistance to raise its temperature to 150 deg Celsius for 220V AC and 24V DC.. Please explain this with required formula...

I'm building an AC to DC power supply for a class and my question mainly revolves around the input and output of the whole thing. My source of confusion is where to include my DC output in a circuit such as I would assume that it would be the leftmost node of that full bridge rectifier...

If you have an alternating voltage source in series with one inductor what happens? The book has a graph of the alternating voltage source and the current through the inductor. What I don't understand is how there is current in the inductor at t=0. If you look at how I solved the problem I...

Sorry but have only a basic understanding of electric circuits? My understanding of DC circuits is that the p.d between either terminal of the power supply is the electrical energy used by the electron in moving through the circuit. How does the voltage change in an AC circuit if the voltage is...

Hey guys, My understanding of circuit analysis and the like is very minimal, and I have had a certain lack of understanding about something for a long time, and I feel I need to get a solid answer. I understand the fundamental difference between a voltage or potential difference and a...

Hi, I have to detect overvoltage on each of the 3 phases (individually) of a 3 phase AC signal. The 3 phase AC source has a neutral that is grounded and I have to use the same ground plane for my PCB. I was thinking of using a full bridge rectifier for each of the 3 phase but the problem is...

Homework Statement I need help with determining the current through the 1Ω resistor. http://img403.imageshack.us/img403/5422/acex22.jpg The trouble I have is that the voltage sources are phased as given in picture, and I got stuck on how to deal with these phases when calculating the...

Hello experts! AC emitter resistance is given as, rE'=25mV/iE My question is that what does this 25mV tells us? and where does it come from? Thanks in advance.

Hi there I have an Photo Voltaic system size 141 kW DC. It gives me an about 13 000 kW/hr a month.(I'm in Hawaii) We planning to install a new system, size ≈800 kW DC. How can i calculate how much of kW/hr AC i will get out of new system? Is there is any special formula to covert DC to AC...

I am sorry if this may seem like a beginner question (which I am not) but the I find the best way to learn something is to understand it from it's most basic components or operations first. In this spirit I have a question regarding the relationship between voltage and current in AC circuits...