trendski:
Hi,I've looked on the WWW. with Google for a "newbie" tutorial or explanation of the above terms, but haven't been able to to grasp it easily - loads of maths and equations
I kinda get that it's like resistance but applied to AC, and that extends to digital circuits with ON / OFF states and clocks, crystals etc..
I find the fluid analogy of resistance in DC circuits useful for understanding resistance - anything similar for the Impedance and reactance?
cheers
PS My education is in Biology. Been using Arduino for about a year now.
If an AC circuit has only purely DC resistance components in it (including wire and or trace resistance) then the circuit Impedance is equivalent to the DC resistance and simple ohms law calculations applies in the circuit. However if the circuit has reactance components in the circuit either inductive or capacitance components, or both, then the circuit reactance must be calculated separably and then the resistance component is added to that for a total circuit impedance. The frequency of the AC voltage source is also a variable in the calculation as both capacitance reactance and inductive reactance vary by frequency. For any combination of capacitance and inductive in a AC circuit there will be a specific frequency where the capacitance and inductive reactance will be equal but 180 degrees out of phase, so they will cancel each other out for a reactance of zero, and then only the circuit pure resistance will determine the circuit's total impedance at that specific frequency, which is called the resonance frequency of the circuit.
I'm sure that is clear as mud, but it is all explained in basic AC circuit theory, step by step, and is not all the difficult to learn if you follow a good lesson plan, many are out there.
Lefty