Why Power Lines Have Stepped Up Voltage

177

02:15:55

In the top example, the power goes straight through the power lines, and due to the resistance, none is left to light up the 100W incandescent bulb. In the bottom example, the voltage is stepped up so that there is less current and more voltage so that the voltage drop is reduced because of the lesser current and what voltage drop that is still present is less significant since there would have to be a much larger voltage drop to affect the higher voltage. Because of that, even though the power goes through a long, high resistance power line, the 100W bulb is lit up almost as if it were connected directly to the power plant.

published 7 years ago

BillyT

7 years ago

What you are saying is correct.

hurz

7 years ago

@giowix, because the tubes are over 10000 meter separated?

jason9

7 years ago

Maybe he means that the voltage is stepped down because semiconductors work at lower voltages?

zorgrian

7 years ago

Step it up higher... No need for wires, just use lasers to make a slightly ionized path in the air

jason9

7 years ago

@giomix, you were a bit unclear and it took a bit of thinking for me to come to that conclusion, so please try to be clearer next time, especially when your commenting about identical step-up/down transformers being used for one purpose on a circuit where those step-up/down transformers are used for another purpose.

giomix

7 years ago

Yes jason9, you are right, sorry. The example is based on trasformer property constant-power machine (ignoring some energy loss that determine efficiency < 1) . So stepping up voltage on secondary current is stepped down and a resistance voltage drop over line is little. The second trasformer works in reverse manner and almost total energy is delivered. When I thought to power supplies for tubes the only analogy was the use of two trasformers linked in reverse configuration. But there the first step down and the second step up) , just to use low voltage components for regulation of voltage ouput.

hurz

7 years ago

@giomix, tubes are working with relative high voltages and low current. Loudspeaker are better when low ohmic around 8 Ohm is best. Old radios used horrible loudspeakers with resistance of several hundred ohm to be connected directly to a tube, it gave ugly sound and not much power, cuz the loudspeaker were very inefficient. So one trick later was to use one transformer to adapt the impedance mismatch between tube and loudspeaker. Propably this is what you mean and is similar to the problem @jason9 is demostrating here, at least to half of it.

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