Voltage drops - i don't understand

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The discussion centers on calculating the necessary voltage drop across a capacitor in a circuit with a 750W, 100V lamp connected to a 230V supply. The user is confused about determining the current and voltage drop, initially calculating current as I = 750W/100V. A participant clarifies that the voltage drop required across the capacitor is 130V, derived from the difference between the supply voltage and the lamp's voltage. To find the capacitance, they suggest using a capacitor equation that incorporates frequency. Understanding these calculations is essential for completing the problem.
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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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