formula needed help

[searley]

can any one show me how to get the formula for this ?

the reactance of a 1uF capacitor connected across a 50HZ supply is ?

the answer is 3.18kohms i can`t work out how to use the 1uF and what it stands for.

while you are here can you check this out

an electric heater dissipates a power of 3.0KW when connected to 230v a.c supply is ?

i get 13.04 doing it 3000/230 but on the answer sheet it says the answer is 17.7ohms ? how is right

 

[Apache]

an electric heater dissipates a power of 3.0KW when connected to 230v a.c supply is ?

i get 13.04 doing it 3000/230 but on the answer sheet it says the answer is 17.7ohms ? how is right

3000/230 gives you the current

you need V=IR, rearrange R=V/I

230/13 = 17.64ohms

 

[mcgaw81]

Dont know your answer to your first one but i'm sure someone will.

As for the second you have worked out the ampage, however going by the answer they have the are looking for the reisistance. You are half way here,

To get this you would need 230/13.04 which gives 17.64ohms.

Hope i'm right. ?:|

 

[Apache]

Dont know your answer to your first one but i'm sure someone will.As for the second you have worked out the ampage, however going by the answer they have the are looking for the reisistance. You are half way here,

To get this you would need 230/13.04 which gives 17.64ohms.

Hope i'm right. ?:|

I concur macca

 

[mcgaw81]

The mind still works even after these.

Guiness DrinkGuiness DrinkGuiness DrinkGuiness DrinkGuiness DrinkGuiness Drink

 

[M107]

Xc = 1/ 2PIfc

Xc = capacitor reactance

2pi = two pie (because I dont have the pi sybol)

f = frequency

c = capacitance in farrads (in your case it micro farads thats 10 to the -6)

Any help ?

 

[a1]

Pico Farads.

 

[Apache]

Pico Farads.

no - pico is 10 X -12

Micro is 10 X -6

 

[searley]

is this it

1/2xpiex50x10-6 = 3183.09

 

[peach]

see attachment

can any one show me how to get the formula for this ?the reactance of a 1uF capacitor connected across a 50HZ supply is ?

the answer is 3.18kohms i can`t work out how to use the 1uF and what it stands for.

while you are here can you check this out

an electric heater dissipates a power of 3.0KW when connected to 230v a.c supply is ?

i get 13.04 doing it 3000/230 but on the answer sheet it says the answer is 17.7ohms ? how is right

img024.pdf

 

[Andy™]

see attachment

Welcome to the madhouse. answer/formula has already been discussed on this thread though

 

[Andy™]

Capacitive you always divide by 1

formulas are correct but your text isnt as correct...

anything divided by one = what you started with. its one divided by 2piFL

EDIT: where did bobby's post go?!

 

[bobby]

Removed my post because the formula didn't come out right and editing it didnt rectify it so I'll try another way, thanks for pointing out my mistake andy.

Capacitive reactance (Xc) is the opposition to an a.c current in a capacitive circuit. It causes the current in the circuit to lead ahead of the voltage

Xc=

1/

2nfC (ohms)

1/ = 1 over

Xc= capacitive reactance

n= pi

f= Frequency (Hz)

c= capacitance (f)

so,

2xnx50x1 = 314.159

1/314.159 = 3.183ohm

 

[a1]

Pi formulae now added to the "Smiley" section.

pi

 

[a1]

I have set it up to automatically replace the p & i when used together.

 

[Andy™]

I have set it up to automatically replace the p & i when used together.

i noticed. doesnt quite work the way it should though....