Recent content by Qroid

Thanks very much for your reply. I'm confused about this line (quoting from http://lnc.usc.edu/~holt/papers/thesis/holt_thesis.pdf): "The total current through the membrane of any neuron must always equal zero, no matter what the neuron does, because of conservation of charge. However, current...

I think it's a jpg, but I'm not sure. Here's a picture of another equivalent circuit http://upload.wikimedia.org/wikipedia/commons/thumb/1/1f/MembraneCircuit.svg/336px-MembraneCircuit.svg.png

Hi all - I'm preparing a presentation that includes circuit diagram stuff, and it's been a very long time since I've done any of that. For this circuit, http://alford.bios.uic.edu/Images/586%20images/circuit%20model (i.e. a circuit model of an isolated patch of cell membrane), I read that...

Hi - sorry for the confusion! b is indeed floating. I (think) I set this in the circuit diagram, but I didn't explicitly state it in the question. The question is worded by me, so all confusion is my fault! I understand what happens now. Thanks very much - super useful!

There's something I don't understand... If the potential across the capacitor changes, then the charge on the capacitor would have to change. But b is floating, so there's no source of charge for b (no way to get current to it). So how does this work? Specifically, how does the charge on the b...

Hi ehild - sorry to be pedantic, but I just want to make sure I have this right. The voltage at b does not change. Vb=-1V in both situations. The voltage at a does change. Va=0v in situation 1., and Va=1.5V in situation 2. Therefore the voltage across the capacitor, Vb-Va, changes. Vb-Va=-1V in...

From a physiology point of view, calories are burned just holding the weight in a constant heigh. Clearly there's no work being done to the weight in this situation (you're not adding gravitational potential energy to it) but there's some muscle exertion. There's some work being done, but it's...

Hi ehild, thanks so much for your help. I'm embarrassed how rusty I am at this! In the second configuration, a is now at 1.5 V (relative to ground). Doesn't that mean that b is now 1.5-1 = 0.5 V relative to ground? So the voltage difference across the capacitor is still -1 V (b-a)? Is it...

In 1. (see attached), a is attached to ground, so has a voltage of 0 V. The voltage at b is -1 V, so the voltage across the capacitor (Vb-Va) is -1 V. My understanding is so rusty... What happens when a is now wired to the positive end of a 1.5 V battery, and the negative end of the battery...

Thanks yungman. And yeah, that's about where I got to. The thing is that I'm starting from voltage. So, to see if curl(E)=0 I first need to calculate E, but the only way I know to calculate E is by assuming curl(E)=0 and using the approximation E=V/d. Problem. Just to reiterate, what I have are...

Hello, I have electrophysiological data from an array of electrodes. I know the locations of the recording tips of the electrodes. Starting with voltage, I'd like to estimate the electric/magnetic fields around the electrodes. I'm unsure when it's okay to approximate E=-V/d. That is going...