What is Frequency: Definition and 1000 Discussions
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as temporal frequency to emphasize the contrast to spatial frequency, and ordinary frequency to emphasize the contrast to angular frequency. Frequency is measured in hertz (Hz) which is equal to one event per second. The period is the duration of time of one cycle in a repeating event, so the period is the reciprocal of the frequency. For example: if a newborn baby's heart beats at a frequency of 120 times a minute (2 hertz), its period, T—the time interval between beats—is half a second (60 seconds divided by 120 beats). Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light.
Hi,
I am new to world of electronics and to high frequency Domain. But I am working on a design where I have a coax of 30cm length. I have used an external oscillator to generate 7GHz fast falling pulse. I am using a Controller to control the oscillator. Now I have a pulse of about 350ns...
Hi,
Im quite new to frequency and how it effects a circuit with both capacitors and inductor. I have created a simple circuit in Multisim and run an AC-analysis.
Pictures of both circuit and analysis is attachments.
What is happening here.
And arent the circuit also depending on the time...
Homework Statement
The wire has mass 250g and is tied down at both ends. It has a length of 12.50m and a fundamental frequency of 25.0 Hz. It has linear mass density.
Sound travels at 344m/s in air. Calculate the frequency of the sound waves produced when the wire vibrates at its fifth...
Hello guys, I am having a bit of trouble with some homework
So I am told that a photon in a light beam has an energy og 2,12 eV. First i have to calculate the energy of it in joules, and since 1 eV is 1,60*10^-19 Joules 2,12 eV in joules is just 2,12*1,60*10^-19 = 3.392*10−19 J i got that.
Then...
For example, when you have a photon interacting with a bound electron, there is a work function relating the minimum energy photon capable of interaction (given by hf). My question is, what exactly is going on in this situation if the work function is exactly equivalent or less than the energy...
Homework Statement
A slinky with natural length of 3.00 meters, mass of 0.750 kg, and spring constant 18.0 N/m is stretched out along a floor, each end held by a seated person. The final length is 8.2 m. One end is plucked sending a transverse pulse. Find the pulse's travel time there AND back...
So, here's the set-up:
A small stereo speaker is connected to a function generator. A concave lens, bearing a ball is place over the speaker.
Now, the frequency is slowly increased in the function generator. My question is,
Will the ball really bounce at a certain frequency? Because I am not...
Q. A LASER is operating at a frequency f = 6.1*10^14 Hz.
A)Calculate the momentum of the photon emitted by the laser.
B)A helium atom flies towards the laser at a speed of v = 3.5 m/s.During one laser pulse the gold atom absorbs on average 5 photons.Find the speed the helium atom after one laser...
As we know, when the observer is moving away from the source, then the apparent frequency is,
##f_{observer} = f_{source} (\frac{v_{sound} - v_{observer}}{v_{sound}})##
But, if ##v_{observer} > v_{sound}## , ##f_{observer}## becomes negative.
Homework Statement
An inverting amplifier with the DC gain of -9 (V/V) is built with an op amp having its
DC gain of 105
and corner frequency of 30 rad/s.
▪ Determine the 3-dB frequency of the inverting amplifier.
▪ Sketch the magnitude Bode plot of the voltage transfer function of the...
Homework Statement
Which of the following is a forced frequency acting on the oscillations?
I. A pendulum skims the surface of a pool of water at the lowest point of motion.
II. To keep a bell ringing, a bell ringer pulls on a bell rope.
III. A singer shatters a glass.
Homework EquationsThe...
It is always considered that the evolution of the input reflection coefficient, ρ, of a LTI causal passive system with frequency, f, always presents a local clockwise rotation when plotted in cartesian axes (Re(ρ), Im(ρ)), e.g. in a Smith chart, as shown in the attached figure.
It must...
It is always considered that the evolution of the input reflection coefficient, ρ, of a LTI causal passive system with frequency, f, always presents a local clockwise rotation when plotted in cartesian axes (Re(ρ), Im(ρ)), e.g. in a Smith chart, as shown in the attached figure.
It must...
Homework Statement
[/B]
Parallel circuit consists of 100ohm resistor with 0.4A current, a 0.47uf capacitor with 0.177A current. Both connected across an AC supply, determineHomework Equations
[/B]
The supply voltage
The supply frequency
Current drawn from supply
Power factor of the circuit
The...
Hello to everyone!
First I would like to go through one simple example:
We have two bodies. One is wave source, other is wave receiver.
In this example they are positioned like this:
(source) O=====> (receiver) O=====>
Distance between them is always 1000 m. Let's say that the waves are...
Suppose that I have two sources: 1. 24 VAC, 60 Hz and 2. 24 VAC, 20 Hz
Then I will use it to power into certain load (maybe we can assume a purely resistive load to simplify the question). What would be the effect of those sources to the load? How about the current flowing? I think (1) and (2)...
Homework Statement
Given a uniform bar of length L, which point should you hang it from (between 0 and L) so that you get maximum frequency for small oscillations?
Homework Equations
...
The Attempt at a Solution
It seems like a basic problem, but I don´t know how to start. Could you guys...
Hi there,
I am reading an introduction on trapping atoms in space with magnetic potential. The article said the lab usually use a harmonic potential to trap the atoms and the potentials is in the form
##\dfrac{m}{2}(\omega_x^2x^2 + \omega_y^2y^2 + \omega_z^2z^2)##
and ##\omega_{x,y,z}## has...
Hi everyone,
I am using IRF530 in a half h bridge DC motor driver. The MOSFET is behaving erratically if the PWM frequency is increased above 20 KHz. I checked the datasheet thoroughly but could not find any thing related to maximum operating frequency. Is input capacitance related in any way...
I have got to know that the voltage and frequency of the supply in the power grids is kept as infinity.>! But what is the reason behind it..??
Well for the voltage to be infinity , I have studied that losses are inversely proportional to square of supply voltage ..so higher is the voltage ...
Homework Statement
Before I write the question you should know that my maths is all correct in my solution but I must have used the formulas incorrectly (or used the wrong formulas). I can't pinpoint where I've gone wrong or if I have left a formula out (I'm a teacher solving this question for...
I understand the concepts behind the terms in the title; however, I have a question about how to transform the wave energy itself. I'm working on a science fair project that involves transforming sound energy into electrical energy--I understand this is not a very reasonable method of harvesting...
Homework Statement
Homework Equations
v=fΛ
v=√(T/μ)
The Attempt at a Solution
I know I'm supposed to make an attempt, but I can make heads nor tails of this. Are they changed in a constant ratioo? Does the tension come into play?
The answer given is 0.16m
I got one solution for an simple ode that involving gravity wave frequency . Before going further I have to understand more about gravity wave . So I need your help guys ...
I would like to know how to design an amplifier similar to the attached circuit with set -3db points, the lower on the order of 10Hz, and the higher on the order of 10kHz.
I have designed amplifiers to work with a set gain, but have not dealt with frequency response before.
I designed an amp...
Homework Statement
A simple pressure relief device is shown in Figure Q6.1 below. It consists of a
piston of mass 0.5 kg and thickness 3 cm sliding without leakage or friction into
a cylinder of diameter 5 cm. The bottom section of the cylinder can be exposed
to a varying source of pressure...
So I was just looking around today and stumbled upon something called Planck's law. I saw an equation and quite few more of them that looked like this,
I'm familiar with all of the other variables and constants already, but don't get the E (hv/kT) part, yet. Is E the energy of the photons you...
My goal is to use a single signal to do two things at the same time...when DC signal is applied turn transistor1 off and turn transistor2 on. Then when signal is not applied transistor1 returns to on and transistor2 returns to off. Frequency will be no more than 60Hz.
What would this circuit...
Hi,
I'm analyzing a 3 dof undamped system with discrete springs and masses. Three of the springs have time-dependent stiffness, following periodic law (with period T), they are modulated at the same frequency but with a phase difference of 120 deg one from the other.
So this is my system:
(M *...
We know that frequency of induced emf in secondary coil remains same as frequency of applied voltage in primary coil and I have read that its reason is " there is no relative motion between the coils..".
Actually I am not getting the reason , maybe some fact or concept has slipped from my mind...
Hello,
I've been thinking about what exactly is the doppler effect and I'm not sure I understand it because I thought it meant a change in frequency due to relative motion while at the same time its defined in terms of changing wavelength such as in red shift or blue shift.
Case 1
The...
Homework Statement
this is something i noticed doing homework rather than homework itself. I plot fft output from different frequency signals, i am not sure why power changes with increasing frequency?
Homework Equations
if i take (with MATLAB notation):
time = 0:0.01:10
y =...
Homework Statement
2. Homework Equations
10 Log[10](g/mW)= GdBw
The Attempt at a Solution
I have attached a document of my approach to this question. I would like to know if my approach is correct? Thank you for your assistance
Why do some LED bulbs show clear utility frequency flicker, while others don't? Is it there, but not visible for the weaker lamps because of less amplitude? Is the diffuse bulb coating fluorescent and smooths the flicker away?
Here a comparison of some IKEA LEDARE models, slowed down by factor...
Homework Statement
A mass m = 2.0 kg is attached to a spring having a force constant k = 990 N/m as in the figure. The mass is displaced from its equilibrium position and released. Its frequency of oscillation (in Hz) is approximately _____ . [/B]
Homework Equations...
This is a long post. Sorry...
1. Homework Statement
We are given a spherical capacitor with an inner conductor of radius ##a## and outer conductor of radius ##c##. The space between the conductors is half filled (##a<r<b##) with a dielectric with permittivity...
I am looking into why 802.11a does not permeate as well as 802.11g. I know that they are different freq. Does this mean a different cell size per packet as well?
In S.H.M omega denotes?I am really confused where to put pi=3.14 and where to put pi=180 degrees.In one question while solving for omega when Time period is given from formula T=2pi/omega i took pi=3.14 and got right but in other question in similar situation i.e solving for omega when Time...
I'm just coding a program where I've to calculate the individual frequencies inside an audio file *.wav file.
The modulation is pcm and the information I've is a lots of points, like this:
http://www.renesas.com/media/support/faqs/faq_results/Q1000000-Q9999999/samp_1.gif
To be exact, I've...
Homework Statement
As you stand by a railroad track a train passes with its whistle blowing. As it passes, you hear a frequency shift equal to 21 % of the frequency of the whistle. How fast is the train moving. Express your answer in km/hr.(Speed of sound is 331.4 m/s) Homework Equations
f’ = f...
Homework Statement
Homework Equations
ΣF , ω=√(k/m), f=w/(2pi)
The Attempt at a Solution
I figured since the only forces acting on the block is the Spring force and a normal force in the downward position. Not a hundred percent sure of this though.
For Disc:
ΣFy= Fn - Fg - fs (static) = ma...
1. The problem statement,λ all variables and given/known data
A drum skin is stretched over one end of a pipe, creating a resonant air column with one open end and one fixed end. How long must the pipe be to achieve a resonant frequency of 280.0 Hz? (Use 343 m/s for the speed of sound.)...
There are a lot of florescent proteins in the visible range, but why haven't we fount any above or below that range?
I think a protein that emits radio waves could be very helpful both biologically and scientifically. Are we not looking for such proteins, or do they not exist?
Homework Statement
A coaxial transmission line consists of an inner cylindrical conductor of radius 1mm and a cylindrical outer conductor chosen to make the characteristic impedance 75 ohms. The space between the conductors is filled with a gas that can stand a maximum field of 10^5 Vm^-1...
< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template was used >
How would you determine f0 (frequency of the source) and Vsource when given highest and lowest frequency
Highest Frequency = 640 Hz
Lowest Frequency = 50 Hz
I can't use the Doppler effect...