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Telephone exchanges were built in the days before electronics and it was found that the sheathing of lead telephone cables suffered less corrosion from water when the exchange battery was connected with a negative earth.
When polyethylene sheathed cables and electronics arrived in the 1950's this problem was lessened. The first PNP germanium transistors were suited to this polarity but when silicon transistors appeared in the 1960's the most popular NPN types were suited to negative Earth. It has remained this polarity to the present day.
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Why the dc average voltage is having negative value?
Voltage is synonymous with 'potential difference', and cannot have a positive or negative value (in the sense of charge). So what you are describing is 'potential', which can. So, for example, a battery whose positive terminal is earthed or grounded will indicate a negative potential if a voltmeter is connected between earth and its negative terminal.
Why the earthing pin of a socket in eletrical appliances is long and thick?
At very first the load to be EARTHED before polarities to protect the load and human being
Why neutral is earthed?
Neutral earth is very necessary for observe the unbalaced laod of the 3 phase system. it is also useful for single phase supply and in lighting purpose. neutral earth is also earthed the short ciruit fauly current , which is flowing through neutral. this type it is very essencial for protection and safety purpose.AnswerThere are a number of reasons why the neutral of a supply is earthed (grounded). The first reason is to protect the low-voltage secondary side of the distribution tranformer in the event of a short circuit from the high-voltage secondary side (it will cause the protection on the high-voltage side to disconnect the transformer). The second reason is to establish a datum point for potentials measured on the secondary side of the tranformers -in particular, if the star-point of a three-phase transformer is not earthed, then an unbalanced load will result in unbalanced supply phase voltages, and a potential-difference between neutral and earth -both undesirable and dangerous.
What is an Earthed voltage transformer?
An earthing transformer provides a neutral in a delta connected system.
Should positive go to positive in a circuit?
No, this will not work. Postitive to Negative/Negative to Positive will work.
Are Hyundai getz positive earthed?
no
Why is the earthed side of a circuit negatively-charged ie attract positively-charged ions?
There's no reason that the circuit must be configured that way. There are many circuits, devices, and applications in which the positive side is earthed. For example ... and for some reason that I still don't know after a lifetime in the telecommunications industry ... most telephone systems are powered with negative DC power plants, that is, with huge DC power plants and battery banks whose positive sides are earthed.
When was Earthed to the Ground created?
Earthed to the Ground was created in 1984-05.
Can insulator be earthed?
yes
Does a vacuum cleaner need to be earthed?
no
Should front wheel bearings be earthed?
Front wheel bearings in a car should be well greased but have never heard of them needing to be earthed.
Are double Insulated portable tools earthed?
No.
Why was silk the perfect trading good?
Silk was traded for... i think gold :)
What type appliance must not be earthed?
An electric stove
When removing battery leads what lead should be removed first?
The battery lead that is not the earthed lead should be removed first. If the negative lead goes to ground then first remove positive and vice versa. This is true also for any non vehicular electrical device although the earthed lead is less easy to find but is almost always negative.
Difference between earthed and unearthed cable?
For earthed and un earthed XLPE cables, the IS 7098 part2 1985 does not give any difference in specification. The insulation level for cable for unearthed system has to be more. In simple statement the manufacturers states that 11 KV earthed cable is suitable for use in 6.6 KV unearthed system.The process of manufacture of cable is same. The size of cable will depend on current rating and voltage level.
When was Taipei Exchanges created?
Taipei Exchanges was created in 2010.
