Questions tagged [frequency]

How many times something happens per second, measured in Hz (Hertz).

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4answers
1k views

Can a cheap, low bandwidth, long-distance wifi be physically and electronically possible for public use?

Since facebook and all the social media warfare, I have realized that the internet is awesome, but not very scalable to embedded devices: new generation network standards are still expensive to make ...
8
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3answers
11k views

3-phase Motor Speed Controller

Background If you look at my profile description, you'll see that I'm involved in building and wiring up Carnival floats that are powered by an 800KVA, 415v, 3 phase Generator. Electrically, they ...
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4answers
136 views

Frequency Filtration

I have a signal that consists of N frequencies all with unknown phase and frequency(N) = frequency(N-1) + 2Hz. I would like to selectively scale the amplitudes of some of those signals in such a way ...
5
votes
4answers
8k views

Connecting piezo buzzer with BJT

I have a 4 KHz piezo buzzer and a microcontroller (arduino) that outputs that 4 KHz from one of it's pins. All is fine if I connect the buzzer to the output with one pin and to the ground with another....
12
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2answers
2k 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 ...
17
votes
4answers
16k 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 ...
30
votes
5answers
14k 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 ...
8
votes
2answers
1k 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?
3
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3answers
381 views

Lowering PIC Clock Frequency

How do I lower the clock frequency of a PIC18F2550 and recalculate the peripheral dividers? I'm trying to make it run cooler. Currently, it runs at 12MIPs/48mhz (USB-CDC-ACM).
6
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3answers
12k views

How do I modulate PWM frequency in realtime with a Microchip dsPIC?

I'm trying to change the PWM output frequency roughly once a millisecond using a dsPIC33FJ256GP710, and I'm having mixed results. I first tried this: ...
2
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2answers
343 views

How to get higher frequency from DC power supply?

I desoldered a component, HY-05 Electro-magnetic sound generator, from a broken motherboard. Its DCV is 3~8V, operating frequency 2400 plus or minus 200 Hz. I can get a small metallic sound with the ...
5
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2answers
913 views

Astable multivibrator with increasing frequency

I am wanting to design a circuit that uses an astable multivibrator as a clock source. However the difference being that over time the clock is gradually sped up until it reaches some multiple ...
5
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5answers
3k views

How to deal with a DC adapter with irregular voltage output?

Background information: I tried hard to get a Schmitt-trigger working, but it kept failing. By accident I figured out, that my AC-to-DC adapter produces a very irregular voltage output (I could hear ...
11
votes
8answers
14k 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 ...
28
votes
6answers
24k 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 ...
4
votes
3answers
2k views

Audio Frequency Shift Keying to Arduino

I am attempting to have an Arduino interpret an AFSK signal, this is very vague but can anyone just point me in the right direction for detecting the frequency of the AFSK signal with an arduino?

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