Voltage drops - i don't understand

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SUMMARY

The discussion centers on calculating the voltage drop across a capacitor in a circuit with a 750W, 100V metal-filament lamp connected to a 230V, 50Hz supply. The required voltage drop across the capacitor is 130V, determined by subtracting the lamp's voltage from the supply voltage. To find the capacitance, users should apply the capacitor equation that relates voltage to the rate of change of current, incorporating the frequency of the supply. The current through the lamp is calculated as 7.5A using the formula I = P/V.

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Homework Statement


Hi, this question is really confusing me and preventing me from completing the rest of the question. It is probably a very simple problem but i just don't understand so any help would be much appreciated.

A metal- filament lamp,rated at 750W, 100V, is to be connected in series with a capacitor across a 230V, 50Hz supply. Calculate the voltage drop across the capacitance required, the current, the capacitance, phase angle between the supply voltage and current.


Homework Equations


P = IV
V=IX X = capacitive reactance



The Attempt at a Solution


I think the current is given by
I = 750W/100V?
I don't know how to calculate the voltage drop.Thanks for any help and tips
Debs:smile:
 
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The voltage drop needed across the capacitor to keep the bulb happy is 230 - 100 = 130V. To find the capacitance, look for a capacitor equation relating the voltage to the rate of change of the current (it will involve the frequency).
 

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