# Tag Info

Accepted

### Is there a physical limit to data transfer rate?

tl;dr- The maximum data rate you're looking for would be called the maximum entropy flux. Realistically speaking, we don't know nearly enough about physics yet to meaningfully predict such a thing. ...
• 4,573

### Is the voltage ever undefined?

The voltage between to points in the universe is always defined. But the voltage between two circuits is undefined because (at least from electronics point of view) circuits are abstract models of ...
• 631

### How is data transferred between devices?

It is less of a "sending electrons," and more of jiggling them. Think of a wave, done by the crowd at a sporting event. One person raises their hands high, and then sits back down. The ...
• 43.2k

### How do headphones and earphones produce good bass if tiny speakers can't produce low frequency sounds very well?

There are a few reasons why small speakers have trouble creating bass. Bass is directly proportional to the amount of air the speaker can move. So you want a large cone that can move a large distance....
• 3,486
Accepted

### How electrons move so fast in a electric circuit?

The electrons themselves don't move all that fast. The wave energy is the part that moves quickly. Picture it this way. You have 500 meters of pipe, with a small hole at the other end. The pipe is ...
• 2,736

### Is there a physical limit to data transfer rate?

The Shannon-Hartley theorem tells you what the maximum data rate of a communications channel is, given the bandwidth. $$C = B \log_2\left(1+\frac{S}{N}\right)$$ Where $C$ is the data rate in bits ...
• 461

### Does a Mobius resistor have zero inductance? How would you calculate the inductance?

The inductance can be calculated, but it is first necessary to look at the behavior at very fast timescales of a ns or so. Clearly the two faces of the strip form a transmission line and so, at short ...
• 559

### Why does a capacitor act as a frequency filter?

An capacitor has one intuitive property: Its voltage can't change instantly since its voltage is dependent on the charge it has stored, and charge doesn't move at infinite speeds (there is always ...
• 7,785

### How is data transferred between devices?

I have drawn a diagram to illustrate the mechanisms of how telecommunications work. This is a highly simplified cartoon of what happens. What I’ll be describing is in part often described in Telecom ...
• 929
Accepted

• 15.2k

### Why two separate batteries in a circuit don't work?

The short answer is that you need a complete circuit for a battery to work. However, I find a longer answer to be very useful to help with understanding. If you have a circuit, you are solving a ...
• 43.2k
Accepted

### How come a mobile phone signal is blocked by aluminium foil, but Wi-Fi gets through?

A matter of thresholds The reality of spread-spectrum is complicated but let's imagine that the WiFi router and cell phone tower have both allocated 1 Watt to transmit to your phone, and it in turn ...
• 6,655
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### Why does my TV screen stay dust-free while other screens do not?

It is unlikely that the electronics of the device is responsible for that. The times of high static voltage in TVs are long gone. The only electronic thing I think could be responsible for that is ...
• 6,965

### Pn junction voltage drop?

1) If the n and p doped regions are externally connected using a perfectly conducting wire, why will not any current flow? In thermal equilibrium no current can flow if one connects the two sides of ...
Accepted

### Why doesn't the Earth's magnetic field affect electronics?

Well, it does. The Earth's magnetic field is about half a gauss, or $0.5\times10^{-4}\rm\,T$. So if you have a meter of wire carrying one ampere of current from east to west, it'll feel a magnetic ...
• 75.7k