Electrical Engineering

Nowadays, you can buy DC to DC convertors that do the conversion in a single module.

A cheaper solution, however, would be to use a chain of diodes - each diode will drop 0.7 volts so 4 diodes will drop 2.8 volts, reducing 12 volts to 9.2 volts.

Direct current commonly known as DC is the current which does not change it's direction of flow, but the magnitude can vary with time where as alternating current known as AC changes it's polarity with time it is not uni directional. the frequency of AC varies but DC donot contain such a feature it's frequency is zero.

Isolation transformers block transmission of the DC component in signals from one circuit to the other, but allow AC components in signals to pass.Transformersthat have a ratio of 1 to 1 between the primary and secondary windings are often used to protect secondary circuits and individuals from electrical shocks.

If the area you're referring to is the cross-sectional area of the conductor: you can think of the cross-sectional area of a wire as the thickness of that wire. If you bundled two wires together in parallel, that would be a bit like having one, thicker wire, wouldn't it?

So increasing the area is analogous to adding more pathways for current to travel in parallel. Metals carry current on their surface, but also through electron "bands" in their interior -- increasing area means adding more bands = adding more pathways. And adding more pathways reduces resistance.

in order for electric potential to bridge a gap in an insulating substance, the potential first has to be high enough to ionize the substance. (in air this potential is around 1 million volts per meter) secondly, the energy has to have very few other paths around the gap, otherwise it will just take the less resistive path. once the substance ionizes enough, the electrons in the substance's atoms will go into a higher orbit and turn the atom into a conductor. with a dc current this causes an arc, not a spark. with ac the voltage hits 0, 60 times a second so the spark strikes repeatedly, unless the spark has enough current to stay "hot" through the zero-crossing (as it is called) this last effect is exploited in welding where the voltage is very low but an arc must still form.

Possibly. You need to check the rating on the device. Many compressors can operate on either 50 or 60 Hz.

power spectral density (PSD), which describes how the power of a signal or time series is distributed with frequency. Here power can be the actual physical power, or more often, for convenience with abstract signals, can be defined as the squared value of the signal, that is, as the actual power if the signal was a voltage applied to a 1-ohm load.

Since a signal with nonzero average power is not square integrable, the Fourier transforms do not exist in this case. Fortunately, the Wiener-Khinchin theorem provides a simple alternative. The PSD is the Fourier transform of the autocorrelation function, R(Ï„), of the signal if the signal can be treated as a wide-sense stationary random process.

The power of the signal in a given frequency band can be calculated by integrating over positive and negative frequencies.

The power spectral density of a signal exists if and only if the signal is a wide-sense stationary process. If the signal is not stationary, then the autocorrelation function must be a function of two variables, so no PSD exists, but similar techniques may be used to estimate a time-varying spectral density.

V3= Voltage across the supply

V2= voltage across inductive load

V1= Voltage across known resistance

R= Known resistance

Cos (Phi)=(V32-V12-V22)/2v1v2

power = (V32-V12-V22)/2R

Three phase electricity is generally used when you have a high power device, such as a motor, that benefits from the three phase design. Since this involves high power, there will be no "portable and small" device to convert from single phase to three phase. Certainly, you could have a small electronic inverter, or a motor generator set, but to make sense, you are not talking "portable and small".

Connect a good quality three pin, 15 amps plug the geyser cable with green wire connected to the earth terminal (thicker pin in the plug). If the geyser is to be fitted permanently at one location only, then it is advisable to connect it with a D.P. Switch to avoid burning of wires due to loose connections in three in plug and socket.

Electric motor.

Age really irrelevant... number of hours used real criteria for life of unit. Not many high speed (1500 rpm) generators used past about 20-25,000 hours (can be about 3 Years if continuous base load) or 20-30 years if standby power only. Low speed engines (<=750rpm) can be several times that if heavy duty type.

Ammeters must always be placed in series in a circuit, otherwise they will not work babes :)

The English term 'leakage' can have several meanings, including:

1. an unwanted discharge of a fluid or gas from from a container which was designed not to leak;

2. an unwanted leakage of electrical current from something (such as a battery) which should not normally lose any current when it is disconnected from a circuit.

Even though it is connected to a 9 volt source, it is still a resistor.

Answer: Inductive reactance is the opposition to the change in current in an electrical circuit and is abbreviated Xl.

Answer: The opposition to current flow is called resistance (for DC), or impedance (for AC; often just called resistance); the unit for both is the ohm.

The Davy lamp was used to tell the miners if they hit a spot of dangerous gas's flame would go out every time they hit a spot of dangerous gas and because of that little lamp allot of miners lives were saved.

Will the principle operation is very complex and would require a fair amount of reading in a text book. But the simple operation of a split phase motor is when a single phase motor has two windings. The main operating winding a and auxiliary winding used to create a rotating magnetic field. The main winding is large wire with lots of turns so under locked rotor conditions it is seen as a large inductive reactance and the aux. winding the smaller wire with fewer turns so it is seen a mainly resistive. This 90 degree phase shift is used to produce more starting torque. If a resistive split phase motor aux. winding is switched out shortly after starting. The aux. winding can also be phase shifted by using a capacitor installed in series with it. This is in the case of capacitor start and capacitor run motors.

Yes, especially if that heater does not have any electronic component inside since it will be damaged if operated at a frequency other then it's rated frequency. But, most electronic devices have been made such that they can work on either 50/60Hz. It's still advicable though to check on the heater's body,at it's supply cable's entrance, for it's frequency.

link is provided in neutral path of ac supply because it should provide a path for unbalanced currents , if we use fuse ,fuse may blow of and damage the entire system and also unbalanced currents may be more than the fuse rating

The purpose of the first "request for comments" (RFC) document that was published on April 7, 1969, was to allow engineers and others to discuss ideas, research, and methodologies in a public forum. Many consider this to be the "birth date of the Internet."

core companies for communication engineering

Four number earthing are essential for installation of transformer as under :

1) Two earthing for transformer body.

2) Two earthing for Neutral Point.

Note : Numbers of earthing may be increase as per the client requirement.