Electrical Engineering

Because the ampere is the SI unit of measurement for electric current. It is defined in terms of the magnetic effect of an electric current -i.e. the force between two, parallel, current-carrying conductors, expressed in terms of newtons per metre length.

Not sure

The electrical resistance of a light bulb increases when it is turned on

As a resistor, the tungsten light bulb has a positive resistance coefficient.

This means that the electrical resistance goes up when the filament becomes hot.

For example, a 100 watt light bulb operated at 120 volts - it does not matter if it is AC or DC for this calculation - will have a resistance of 144 ohms when hot and draw .833 ampere.

When cold the filament typically has a resistance of only 10 ohms which increases as the filament heats up.

There is no easy answer to this.

Firstly, it depends on the fridge. Obviously a huge double-door refrigerator will consume a lot more energy than a tiny bar fridge.

Also, they only consume a lot of energy when the compressor is running. The compressor will turn on when the thermostat (ie: temperature sensor) shows that the temperature inside the fridge has gone up too far. How quickly this happens (and how often) will depend the temperature outside the fridge, compared to what temperature you've set the dial to inside.

So, a fridge will consume far less energy on a Winter's night, than it would in the middle of a hot Summer's day. And it will consume more energy the lower you set the temperature dial, because it has to work harder to keep the fridge colder.

Having said all of that, an average 16 cubic-foot frost-free fridge has a consumption rate of around 700 watts. But, it might only be operating at the full 700 Watts, say, 20% of the time. So, your power consumption in that case would be 140 watts per hour, or 0.14 KWh (kilowatt-hours - the correct term for power consumption).

Generally, for a new fridge in the store, you can look at the sticker on the fridge, which will tell you its consumption rate in KWh. Or, if it's an old fridge you already own and the stickers are all gone, you could buy a power consumption meter from the hardware store. Basically, you unplug the fridge (oven, TV, whatever), plug in the meter, then plug the fridge into the meter. Run it for a couple of days, and the meter will tell you how much power your device has been consuming.

To further complicate things, the wattage rating actually depends on the power source used. In America, you have 110 volts, whereas in Australia, for example, the voltage is 240. This actually changes the wattage calculation, so the same fridge will have difference consumption ratings in different countries. The 700 watt example above was obtained from the US Department of Energy, so it applies to a 110-volt power supply.

I told you there was no easy answer!!!

If the transformer is three phase the calculation is I = 30,000 / 1.73 E.

If the transformer is single phase the calculation is I = 30,000 / E.

(Where I = current and E = secondary voltage)

It is important to note the voltage in the first formula is line to line (typically how it is specified in three phase power systems), and the second formula it is line to neutral.

The types of dc-dc converters are the ones with isolation and the ones without isolation. Isolation makes sence only into very high or very small ratios of Vin / Vout. Vin is the Voltage input and Vout is the voltage output of the converter.

The isolation is applied between input and output circuits by using a transformer.

The main types of converters are buck,boost and buck-boost (without isolation) and Cuk, Flyback and Forward (with isolation).

Wow that is hugely dangerous and a risk of fire. They get hot because you are running a large amperage through them, melting cause it is overloaded.

For example. If you had a 20 amp breaker, and 12 gauge wire (20A), and a 15 amp recepticle. Then the most you would want to run on that recepticle is 12 amps continuously, 15 amp peak non continuous. If you replaced the recepticle with a 20 amp recepticle you could run 20 amp peak, or 16 amps continiously. You could not go with a higher amp outlet as the circuit only has 12 gauge wire, and a 20A breaker.

If you plugged something with a 30 amp draw into said outlet you would get the outlet hot.

find out how many amps you are drawing off the outlet in question, then check the gauge of the wire in the wall, and the rating of the outlet and breaker that outlet is off of. Then we could decide what to do next.

Well,Being a Electrician, my advice is if you have to ask question about that call a Electrician IMMEDIATLY!!!!It could be a number of things.A loose wire in the back of plug in,worse yet a broken wire that keeps rubbing together ,(EXTREME FIRE HAZARD)Electricity is nothing to fool with if you are not trained.BE SAFE<SMART.Turn circut breaker OFF.CALL ELECTRICIAN

Really,cmon. Residential pulling that much power off ! outlet.....look outside the box!!how old is house would be first question

If all you have is a voltmeter, then resistance can only be calculated. If you know the total volts applied and current, either total current if in series ckt or current through the component if parallel type ckt, then the following formulas apply: R=Eapp÷It (series ckt) R=Eapp÷IR (parallel ckt)

There is no difference in the cables. The only difference is the type of electrical power being transmitted. AC or DC applications use the same wires.

with a voltomiter

A multitude of things depending on their capability. Typical multimeter functions include:

- Measuring current;

- Measuring voltage;

- Measuring Resistance;

- Measuring continuity (i.e. whether circuit is complete so electricity can pass through it);

kvar can be calculated as follows the a product KVA andt the sine of the angle between the KVA and KW.

Note that this is an engineering convention, not a concept from pure physics. When you multiply voltage by current, the total "power" in volt*amps can be a combination of two types of "power". 1. active power = V*I*cos(theta) and 2. reactive power = V*I*sin(theta) where (theta) is the phase angle between the voltage and current. A physicist would say that V*I*sin(theta) is NOT power since it is performing zero work.

As well as motors, contactors also have kW and Ampere ratings. Have a look on the name plate of your motor and you will see its maximum current draw (amps). Select a contactor with a current rating greater than this.

The effects of electrical shock are many. Some examples... * Tingling * Spasm * Pain * Burned flesh * Fire * Death

The formula you are looking for is I = W/E.

When an n-type semiconductor is further doped with pentavalent atom, four of the atoms are tiedly bond through the process of covalent bond and one electron is weakly bound and free to move as the temperature rises.

By rubbing two synthetic materials together will induce a positive charge in one of the items, for instance walk over a synthetic carpet with synthetic sole shoes and touch something that is negative will generate a spark that can be shocking.

Higher capacity (higher KW rating) motors take huge starting current to get over the starting torque. To avoid the high inrush of current, star delta starter is used. When started, the motor gets connected in star for few seconds and switches over to Delta and continues to run in delta. In this case motor is designed to run in Delta.

Divide by your number of phases 1 or 3 then divide by your Voltage. If its a 3 phase supply Voltage you need to divide by your 3 phase voltage for balanced loads and by your single phase voltage for unbalanced loads requiring a neutral.

To close a circuit in electrical terminology is to close any open devices that are in series with a connected load. Once this happens the current will flow through the load and the load is then termed as energised. In the case of a motor circuit the motor will operate. In the case of a lighting circuit the lamps in the circuit will energise and light the area in which they are installed.