31
votes
Why do radiation hardened IC packages often have long leads?
It isn't directly related to radiation hardening, it is related to the packaging. Rad-hard and other high-reliability parts often come in flat packs. The user is expected to form (bend) and trim the ...
- 16.6k
27
votes
Accepted
Are there any advantages to using rigid RF coaxial cables?
So, are there any advantages to using rigid RF coaxial cables?
First, the product you show might be semi-rigid rather than rigid cable.
In either case, the main advantage is lower loss, because of ...
- 132k
26
votes
Accepted
Why do radiation hardened IC packages often have long leads?
Taking the example of the chip in your picture (RHFAC14A - datasheet,) they aren't always in the flat package with long leads (FPC-14.) They are also available in DILC-14, which looks more like a ...
- 73k
25
votes
Accepted
Can antennas be viewed as light sources?
You are right, antennas and light sources are equivalent constructs. But the mathematics of light sources is not as simple as you seem to think.
The reason why most of the answers so far see them as ...
- 8,506
23
votes
Can antennas be viewed as light sources?
For some cases, you can: If you have a large directional antenna, it might, from very far away, simply look like a beam-generating "flashlight" for radio waves. That breaks down very quickly if the ...
- 98.3k
22
votes
Accepted
How much power is radiated by cell towers?
There's no general answer.
First of all, you have a misconception about GSM, 3G, 4G:
The frequency bands you list are some of the frequency allocations for these networks. These are different ...
- 98.3k
15
votes
Accepted
What is a "half latch" in an FPGA?
A half-latch is a gate with positive feedback implemented with a weak pull-up transistor:
simulate this circuit – Schematic created using CircuitLab
When the input is actively driven, it ...
- 26k
13
votes
Accepted
Are chicken bits left in space-qualified ICs?
The definition of chicken bit in Wiktionary is incorrect, and the extension by OP [as hardwired] is even more wrong.
The chicken bit is a configuration bit (software configurable! and usually ...
- 41.8k
12
votes
What size of hole do microwaves eventually pass through?
Wah! WAH!
Ok, you're putting yourself and your friend in deadly danger.
First of all, your 29$ device is not a substitute for proper RF qualification. It simply isn't. You might be able to find a ...
- 98.3k
12
votes
Accepted
Magnetron and microwave
Unfortunately, it is possible to make the magnetron work outside the oven, but as the comments have said, this is a really bad idea. Do not fire up a magnetron after removing it from an oven.
You ...
- 171k
11
votes
Accepted
What is the acceptable margin for radiated emission on an European CE device
It's a limit, defined in CISPR 11 and other places. So anything below the limit is fine. If you're at the limit exactly it's a bit fuzzy situation, I can't remember off hand if the limit is up to and ...
- 3,686
10
votes
Microwave starts working when door opens - how dangerous is it?
It is dangerous to humans because it heats up things that contain water.
You contain water. Some parts of you can't deal with this added heat (your eyes) and will be damaged first.
It also fries ...
- 23.5k
10
votes
Are there any advantages to using rigid RF coaxial cables?
From a mechanical point of view, a rigid (or semi-rigid) cable has the advantage that they will support themselves. That means that you don't have to worry about them getting pinched or stuck between ...
- 12.6k
9
votes
Does an electrical outlet radiate EM waves?
Adding the wires is a bit pointless as there are already wires (in the wall) leading to the socket, and they also radiate EM waves just like the wires added by you.
So that answers your question: ...
- 81.1k
8
votes
Can antennas be viewed as light sources?
Firstly, "light" on its own usually means "visible light". Antennas do not emit visible light.
We can more correctly say that light is EM radiation and antennas emit EM radiation.
Why can't we ...
- 46.9k
7
votes
Does an electrical outlet radiate EM waves?
Yes, it will radiate a 60Hz (or 50Hz depending on where you live) wave. It will be weak. Very weak. So weak that there's no point in worrying about it.
The radiated power depends the wavelength ...
- 73k
7
votes
Microwave starts working when door opens - how dangerous is it?
IF the oven heats with the door open then
THE OVEN IS HORRENDOUSLY LETHALLY DANGEROUS AND
IT MUST NOT BE USED
It is possible that the light and fan operate when the door is open BUT that the oven ...
- 151k
7
votes
Accepted
Physics of Dirty Electricity?
What exactly is "dirty electricity"?
This term isn't a technical one.
We might say a power line is dirty if its voltage doesn't vary according to the 50 or 60 Hz sinusoidal waveform we normally ...
- 132k
7
votes
Accepted
How does selecting a higher permittivity substrate in patch antenna reduce its size?
Here's an easier explanation:
We know the 2-plate capacitor formula:
$$
C=\epsilon_0\ \epsilon_r \ \frac{A}{d}
$$
Where \$\epsilon_r\$ is the relative permittivity of the substrate, \$A\$ is the area ...
- 38.1k
6
votes
Accepted
How 3mG can be dangerous if the Earth's magnetic field is 500mG?
It is all about frequency. The 3 milliGauss limit is referring to high-frequency fields. High-frequency magnetic fields induce electric fields, which cause currents in human tissue. These currents ...
- 2,822
5
votes
Accepted
Can a magnet cause a microwave oven to unsafely radiate energy?
If I understand correctly, this was due to the deviation of the electro-magnetic (EM) radiation beam from its intended target, as influenced by the speakers' magnets.
No. There's no "EM radiation ...
- 98.3k
5
votes
Am I exposed to high levels of radiation at my job?
A lot of people worry about health effects of electromagnetic radiation, and you'll find a lot of scaremongering misinformation on the web, but it is generally agreed by doctors and scientists that ...
- 1,488
5
votes
Long term health effects of a gsm modem
The fears are unfounded - both technologies are fundamentally safe. The only conceivable damage from radio waves is heating of biological tissue and and Specific Absorption Rate (SAR) testing is ...
- 4,679
5
votes
Accepted
Insight into cavity resonators
Each antenna is able to excite almost any mode, and will. The only modes that won't be excited by an antenna are those for which the antenna is at a node of the mode, a point where the standing wave ...
- 171k
5
votes
Insight into cavity resonators
if I am correct these modes will be the same for each antenna
Not exactly. Modes themselves only depend on frequency and geometry of the cavity indeed.
However, which modes will be excited within ...
- 5,811
5
votes
Are there any advantages to using rigid RF coaxial cables?
I expect the isolation is also better, and the crosstalk is lower. Thus your ultimate system dynamic range will be better, which may be crucial for battlefield survival or to detect more planets ...
- 34.6k
5
votes
Practicality of Faraday door
It doesn't matter what the seal is mechanically, it has to be conductive.
The contact doesn't need to be continuous, it can leave non-conducting slots of length L. However, the seal will be ...
- 171k
5
votes
Accepted
Why does placing an antenna far from the wood increase the efficiency of the antenna?
Wood has an approximate water content of about 10%. Water has a dielectric property that is vastly different to air. The dielectric constant of water is about 80 times higher than air or a vacuum.
A ...
- 467k
Only top scored, non community-wiki answers of a minimum length are eligible