impedance and resistance whats the difference

[zappy]

Are they just the same thing?

 

[LarryFine]

Are they just the same thing?

Think of impedance as AC resistance, because it takes into consideration the effects of AC on capacitance and inductance, collectively known as reactance.

Impedance is basically resistance plus reactance.

 

[zappy]

Thanks Larry.

 

[shamsdebout]

Think of impedance as AC resistance, because it takes into consideration the effects of AC on capacitance and inductance, collectively known as reactance.

Impedance is basically resistance plus reactance.

Thats a very clear and concise answer. For a resistor resistance and impedance are the same.

 

[zog]

Z=R+Xl+Xc, thats the simple answer, but they need to be vectorally added.

 

[LarryFine]

Z=R+Xl+Xc, thats the simple answer, but they need to be vectorally added.

Good grief! I'd hate to see the complicated answer! :roll: D)

 

[480sparky]

Good grief! I'd hate to see the complicated answer! :roll: D)

Here ya go:

 

[charlie b]

Good grief! I'd hate to see the complicated answer! :roll: D)

Too bad:

Z = R + (j*2*Pi*f*L) + (1/j*2*Pi*f*C)

 

[LarryFine]

Too bad:

Z = R + (j*2*Pi*f*L) + (1/j*2*Pi*f*C)

Oh, stop showing off.

Besides, I've used those formulae when messing with audio crossovers.

 

[augie47]

Here ya go:

defines my sentiments when I read some of the answers avaiable on the Forum. There a truly some verrrrrrryyyy intelligent folks posting here. Often so far over my head I can barely feel the air.

 

[zog]

Good grief! I'd hate to see the complicated answer! :roll: D)

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/impcom.html#c1

 

[iaov]

One quick point not mentioned directly. Reactence does not exist in a DC circuit.

 

[Besoeker]

Oh, stop showing off.

more simply:
Z=sqrt(R^2 + X^2)

X being Xl - Xc

 

[SAC]

One quick point not mentioned directly. Reactence does not exist in a DC circuit.

Yes, theoretically true - but "DC" is often used to label systems in which the current is not actually constant. For example, the world of DC electronics is now dominated by reactive effects due to high switching rates. Even though the voltage supplies are at a constant voltage, the loads are often switched on or off very rapidly, giving rise to significant reactive effects. However, the terminology and math used to calculate the effects are different, and is called "transient analysis" vs. "AC analysis" - two different ways to make sense of the same underlying physics.

 

[RonPecinaJr]

Too bad:

Z = R + (j*2*Pi*f*L) + (1/j*2*Pi*f*C)

I hope that's not on the exam.

 

[drbond24]

I love this forum.

First, there was a simple question.

Then, there was a simple answer followed by a polite thank you. Problem solved.

And then there were 13 more posts. I couldn't help but join in the fun and add one myself.

Here I am! Ta-da! :grin::wink: