^+1 If things were too easy people without iron rings on their fingers could do it too. ;-)
-Bruce
^+1 If things were too easy people without iron rings on their fingers could do it too. ;-)
-Bruce
P = I * V is always true, V = I * R (Ohm's law) is not always; they are independent equations.
One can use Ohm's law to get variations
P = V^2/R
P = I^2 * R
but these depend on Ohm's law, and so are not always true; as such it is best to see the last 2 as derived, and not fundamental.
True, a capacitor and inductor have a frequency dependent imaginary impedance, and together with resistance in a circuit they form a complex impedance; one needs to know about complex numbers, which have a real and imaginary part. Imaginary is a rather unfortunate name, as they are as real as real numbers.
Practical Electronics for Inventors, 4th Ed, by Scherz and Monk is a good place to start as well as being very affordable; but be forewarned about the many typos and errors in this text.
Last edited by ashiekh; 07-05-2018 at 01:40 PM.
Yes, in a general sense, you have to account for complexes of reactive components. Even for pure DC, though, components often have complex behavior that can't be modeled as pure resistance (although they usually have a resistive component). For instance, a DC motor will include resistances from the rotor coils, brushes, and field coils (although those are separately measurable) as well as back EMF generated on the rotor coil.
I prefer Electronics Principles by Malvino. His approach using successive approximations of components is brilliant and clear, I think.
I believe my copy is the 6th Ed as well. I hope you enjoy reading it.
Came in yesterday, but I haven't really started it yet.
That's where some got into trouble changing stuff and think that really matters...they designed it all for a reason and matching PWM, Impedances frequency dependent etc, as well stated it's not just resistance.
LOL! Why does this 10+ year old thread continue to thrive!!!!????