How many times something happens per second, measured in Hz (Hertz).
26
votes
8answers
2k views
Why do utility companies supply at a frequency of either 50/60 Hz?
It just struck me that Utility Companies world-wide supply domestic users at either 50/60Hz. It could have been selected to be 10 Hz, or 100 Hz ... whatever
Was 50/60 chosen at random? Is there some ...
19
votes
6answers
3k views
How to convert AC to DC
I am designing a circuit that needs to output 5VDC @ 1A. I'm trying to use a wall transformer to step the voltage down to 12VAC. The next step is the diode bridge and ripple capacitor.
The ripple ...
18
votes
4answers
2k views
Why does a faster clock require more power?
If you overclock a microcontroller, it gets hot.
If you overclock a microcontroller, it needs more voltage.
In some abstract way it makes sense: it is doing more computation, so it needs more energy ...
18
votes
6answers
657 views
How precise is the frequency of the AC electricity network?
If I make a digital clock which first detects the AC frequency roughly (whether it is 50, 60, 100Hz, etc), then uses it as its clock pulse source, how precise would it be? Would it work world wide ...
16
votes
5answers
684 views
What are 12.000393 MHz crystals used for?
I found them on www.digikey.com, and they're apparently made by different manufacturers, so there must be some use for them. What are they used for?
edit
and why? The 2400 baud modem doesn't offer an ...
14
votes
3answers
802 views
Negative frequencies: what is that?
I know that when the frequency is 0, the voltage will be pure DC. But in DSP and Digital Communication, I have seen mentioning of negative frequencies which I dont quite understand. For example, like ...
11
votes
5answers
439 views
Frequency limitation for homebrew CPUs
While looking into some custom built CPUs I've noticed the frequencies at which they operate are relatively low compared to modern CPUs (in the order of several MHz). Is there an electronics ...
11
votes
2answers
506 views
Why is a lower switching frequency more efficient?
I'm designing a 10V to 3.3V step-down converter. Looking at the LT8610, the applications example shows two similar circuits that have different switching frequencies.
The Efficiency vs Frequency plot ...
10
votes
2answers
444 views
Frequency ranges that causes a hazard to humans
I hope many people might feel little awkward to see this question. But I feel this is important. Because in my place where I am living I can get a radio (Audio Receiver) very cheaply. I don't know ...
9
votes
8answers
10k views
Maximum sample rate of Arduino Duemilanove?
G'day all!
I have an Arduino Duemilanove hanging around spare at the moment and thought I might try a few audio interfacing projects. I'm just wondering what sort of sampling frequency I can achieve ...
8
votes
4answers
357 views
Is there a device that converts any AC frequency to 60 hz?
If I have something like a windmill generator that generates AC current, but at variable frequency, what device(s) would I need to convert that variable frequency into a constant 60hz frequency, so ...
8
votes
3answers
2k views
How critical are UART frequencies?
I'm going to be using an 8 MHz crystal to run my microcontroller at 16 MIPS (PLL 4x, 2 cycle instructions.) However, 8 MHz doesn't divide into any UART frequencies AFAIK... so how critical are these ...
7
votes
2answers
605 views
Is it true that the power line frequency is kept accurate by atomic clocks?
I've heard rumors that the power line frequency is kept stable and accurate by syncing it with atomic clocks. Is this true? What kind of accuracy does it have? Is this true everywhere?
7
votes
1answer
402 views
Characterization of bypass capacitors
I was reading through a few post including Decoupling caps as well as this app note Xilinx Power Distribution Network.
I have a question regarding capacitor values within a power distribution system. ...
6
votes
2answers
585 views
4 Hz Stable Frequency generator
Whats a good circuit/design that will generate a very stable 4Hz signal (to feed into a counter) that won't drift with temp / time.
It's not so important that its exactly any particular frequency, ...
