CURRENT AND VOLTAGE

ELI the ICEman cometh!

Plz make me understand.....

Voltage across a capacitor cannot change instantaneously. Current has to change first. Therefor, I (current), in a C(apacitor), comes before E (voltage).

Current through an inductor cannot change instantaneously. Voltage has to change first. Therefor E (voltage), in an L(inductance) changes before I (current).

The old[*] ELI the ICE man.

Grocery and liquor stores may still have an Eli.

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Thank you for helping me out.

Sorry you didn't like my response. :-(

Reactance.

Hope This Helps! Rich

@rich:can u tell me how the reactance is responsible for phase difference?

Reactance is not responsible for a phase change. Reactance of a capacitor and reactance of an inductor have units of ohms.

A google search for "reactance is responsible for phase difference?" found this link:

That resource is approved.

Globemaker Inscribed thus:

Now try reading the next page !

I _can_, but I think you're either supposed to get that from your textbook or your teacher.

Good Luck! Rich

--- @BBC:

Here, I'll take crack at it:

When a voltage is applied across a conductor and charge starts to flow, a magnetic field is generated around the conductor which causes a voltage to be generated in the conductor which opposes the applied voltage.

This opposition is in addition to the ohmic resistance of the conductor, and is called "Inductive reactance" or, written symbolically, "Xl" (X sub L)

Now, since time is nature's way of keeping everything from happening all at once, the magnetic field doesn't build up instantaneously and, as a consequence, as the voltage across the inductance varies, the current through it won't fall in step.

Do you understand?

-- JF

You know, I think the best way to understand about R, C and L might be to build circuits and measure things with 'scopes. (and the proper scope probes) But I can't remember every doing that in college.

George H.

Instead of investing all that time and all those resources, why not just use SPICE?

Think about a capacitor charging through a resistor. When you apply the voltage, the capacitor starts charging with maximum current and minimum voltage across the capacitor. As time passes, the capacitor voltages increases while the current decreases, since the voltage across the resistor becomes less and less, and so does the capacitor current. So, the current and voltage of the capacitor are out of phase, since one will reach a maximum at the same time the other reaches a minimum. The capacitor voltage reaches a maximum when the current is zero, and visa versa. That's 90 degrees. The inductor is the opposite, where current starts at zero and rises, while the voltage across the inductor falls.

-Bill

Hmm, Yeah the difference between a simulation and real life. No arc's when you unplug the coil at full current in the simulation.

George H.

Confucius say: I hear and I forget. I see and I remember. I do and I understand.

Hope This Helps! Rich