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Feb
1
awarded  Revival
Oct
19
accepted Cu/Zn in salt water voltaic cell peculiar behavior — any explanation?
Oct
16
comment Cu/Zn in salt water voltaic cell peculiar behavior — any explanation?
Actually your artsmanship is great! But what happens when I touch a Zn electrode with a Cu plate? (In your second picture, if the central plate is now copper and it is in contact with the Zn electrode below it?) Why isn't there a loop then also? I guess what I'm asking is, why isn't there a symmetry between the two cases? DoI need to know a bit more detail about how a voltaic cell actually works at the electrochemical level? Thanks...
Oct
15
comment Cu/Zn in salt water voltaic cell peculiar behavior — any explanation?
Hi, may I request out to explain in a bit more detail how touching an electrode with the spare plate is analogous to connecting a battery in parallel? Didn't quite understand that ... especially since I am holding the other end of the spare plate between my fingers -- which are completely dry (even once held the plate with some tissue paper to keep it insulated from my skin). I'm sure you are right (and I seem to remember that if I did the reverse -- touch a Zn electrode with a Cu plate -- the LED got a tiny bit brighter if anything) -- its only that I can't quite grasp the equivalence. Thanks
Oct
14
asked Cu/Zn in salt water voltaic cell peculiar behavior — any explanation?
Sep
12
awarded  Popular Question
Nov
28
accepted Magnetostatic energy density — derivation without introducing inductance?
Nov
23
awarded  Popular Question
Jul
2
awarded  Curious
Dec
29
comment Is there any antenna with a single null?
I was looking for exactly zero power (not merely very low power). Even a single frequency will do.
Nov
16
comment Is there a differential equation that can represent a circuit with an arbitrary voltage source connected acrorss an antenna?
Thanks @WetSavannaAnimal this is great. I was looking for what happens to an arbitrary antenna anyway -- what happens for specific antenna designs are generally well known. This answers my question completely.
Nov
16
accepted Is there a differential equation that can represent a circuit with an arbitrary voltage source connected acrorss an antenna?
Nov
16
comment Is there a differential equation that can represent a circuit with an arbitrary voltage source connected acrorss an antenna?
@AlfredCentauri ... unfortunately, that relation would only for short dipoles. For a small loop, we get $R_r \propto \lambda^{-4}$ ... and for a large dipole, it mutates to a large expression in $\lambda$, as shown here
Nov
15
comment Is there a differential equation that can represent a circuit with an arbitrary voltage source connected acrorss an antenna?
I am aware of the expression for radiation resistance of the dipole -- but you'll notice that it contains $\lambda$, which pre-supposes a sinusoidal excitation. I was wondering if there was any way to way to deal with this entirely in the time domain
Nov
15
asked Is there a differential equation that can represent a circuit with an arbitrary voltage source connected acrorss an antenna?
Nov
12
revised Equivalent circuit for an arbitrary receiving antenna
added 224 characters in body
Nov
12
comment Is there any antenna with a single null?
@user23660 did you mean it is possible or isn't possible? If you mean isn't, my question is -- is it essential for radiation emitted from an antenna in all directions to have identical polarizations?
Nov
12
asked Is there any antenna with a single null?
Nov
12
revised Equivalent circuit for an arbitrary receiving antenna
edited body
Nov
12
comment Equivalent circuit for an arbitrary receiving antenna
Thanks @ArtBrown - I am also cautious about that $\cos \psi$ because of the same reason.