Register to reply

Ac circuit non inductive resistor and a coil..

by herbgriffin
Tags: circuit, coil, inductive, resistor
Share this thread:
herbgriffin
#1
Jan29-11, 02:17 AM
P: 17
1. The problem statement, all variables and given/known data
A non inductive resistor takes 8A at 100 volts. What inductance of a coil of negligible resistance must be connected in series in order that this load can be supplied from a 220 volt 60 Hz mains.



2. Relevant equations
Z^2 = R^2 + XL^2
R=V/I
XL = 2pi(frequency) L(inductance)

3. The attempt at a solution
i have solve the resistance before the coil is added.. R=12.5 ohms....
i am stuck on how to get the value of the coil since there is no given current..
Phys.Org News Partner Science news on Phys.org
Security CTO to detail Android Fake ID flaw at Black Hat
Huge waves measured for first time in Arctic Ocean
Mysterious molecules in space
Phrak
#2
Jan29-11, 02:40 AM
P: 4,513
(Stipud educators. The correct answer to this question is that any finite inductance will "supply" the load!!)

The implied question phrased in more than half-witted manner is, "What will supply the load at the same RMS current?

You know the new voltage. It's 220 VAC. So it's not the same one you used to find R.

Use the voltage divider rule for complex impedance in series. Remember the one for finding the voltage across one resistor that's in series with a second resistor? It looks the same.


Register to reply

Related Discussions
Two resistor RC circuit Introductory Physics Homework 6
Resistor, capacitor and coil with Alternating current Introductory Physics Homework 2
Resistor in circuit Introductory Physics Homework 3
Induction Coil powering a load (inductive reactance problem) Electrical Engineering 23
Unwanted signal in an op-amp circuit (inductive pickup?) Electrical Engineering 7