High frequency Definition and 87 Threads

Hello everyone, I am using a lock-in amplifier SR860 with the aim of reading an optical pulse from a laser break-out board operating at 30 kHz as the reference. The reference signal is not being picked up by the lock-in amplifier. However, it is being read by the oscilloscope. I have used a...

Since high frequency photons have more relativistic mass, should we expect them to bend more than lower frequency lights when traveling through a gravitational field, thus produce a rainbow effect? But we don't seem to experience rainbow effects with star light.

Hello all, I'm playing around with a PIC + LCC Tank to send - at a 5MHz frecuency - some numeric data via BPSK. The receiver is a loop antenna placed in the ground. The sender antena (L) is a ferrite core solenoid (N=10). As having a larger core, or increasing the Number of coils around the...

Hello all, I don't know if this is the correct place to post, but I'm looking to detect all electromagnetic waves around me that have a frequency that is under the visible spectrum. The reason is to try and get some kind of idea of what kind of radiation is around me, so that I can be more...

Please see article here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5412966/?report=classic

Hi all I am doing some research on High Frequency Linear Array beam forming (for imaging sonar). For that purpose, a linear Rx Array of 100 channels have been constructed with inter channel spacing of 14.3mm. A transmitting Tx probe operating at 420 KHz (approx. 300 cycles CW pulse) is placed...

if an antenna 8.2 feet long was coiled up into a coil could it still receive radio signals at 30 megahertz?

Hi, can you please tell me how would I be able to determine the effectiveness of a specific circuit, see in the attached spice file I tried to simulate a circuit , my secondary side is a self generating coil which in spice I had to simulate with mutual inductors aka a transformer, my basic idea...

Hello all PF members! I was wondering about the power dissipated by resistor at high frequency which is: ##P=Re\left \{ U\cdot I^{*} \right \}=Re\left \{ \frac{\left |V^{+} \right |^{^{2}}}{2\left |Z_{c} \right |}\cdot (1-\left |\Gamma \right |^{2} )\right \}##, (1) where: ##Z_{c}## -...

I read the limits of typical ferrite cores and it seems that most sources claim that they tend to work somewhere up to 1 Mhz. Surely they work great under that frequency, but is there any material that could provide a core material for a wide frequency range starting from few tens of Khz up to...

Background of problem comes from Drude model of a metal (not necessary to answer my problem but for the curious): Consider a uniform, time-dependent electric field acting on a metal. It can be shown that the conductivity is $$\sigma = \frac{\sigma_0}{1-i\omega t}$$ where $$\sigma_0 =...

Hello, I am designing a resonant mems accelerometer. It has a resonating beam. We are actuating it by AC voltage + DC voltage. We are going to actuate it at beam's resonance frequency. When I search for papers related to previous studies, I encounter resonance frequencies ranging from 20 kHz to...

I am having trouble getting an astable multivibrator to oscillate higher than 480 KHz. I added a "baker clamp" which gave some improvement, but didn't get me to the target frequency of 816.5 KHz. I am on an iPad and can't post a schematic. I use 2sc6082-1e transistors and bat41 diodes for the...

Hi, initially I have seen that when circuits are exposed to high frequency kirchhoff laws become invalid. According to my search I can not find any derived circuit equations for that case, instead computational electromagnetism method is suggested using maxwell. Is it the only way to make...

Does anyone know if there is a textbook on the design and construction of high frequency oscilloscopes (up to 10 GHz)? I am guessing they would be some form of ADC circuit with perhaps a mixer and could use a lap top as the "DSP" and display. How would such an O-scope be calibrated/tuned...

I was wanting to build a very high frequency electromagnet to test an idea and it requires something in the range of about 1-10 GHz, and I'm unable to find much information on what I'm attempting to do. I understand the impedance will be incredible, along with some other technical issues. Most...

Hi Physics, I have an idea but before i start. I must know am I right. Is it possible? We have a small room with two objects. The first object is a producer of sound waves out of the human hearing range. This object sends ultra sound waves to the second object. The second object start to...

Hello all I need a high K material to cancel out E-field in some direction (induced by electromagnetism). This high K material (above 5000) must work in high frequencies above 10MHz. I did use the ceramics but there is no clue that it will work in that range of frequencies or not. I am really...

I want to produce a 100 volt peak to peak symmetrical AC waveform to light a miniature neon bulb. It strikes at about 90 volts then settles ("clamps") at about 50 volts, according to the spec. I want the frequency to be at least 10 kHz for easy filtering because the circuit will also be passing...

Hi everyone, I am trying to understand that why do we use open circuit terminator for wave guides or any RF element such as coupler and etc. I know if we just leave it open, it does not work as open circuit. But why?

Homework Statement a) Derive the Rayleigh-Jeans distribution by taking the low-frequency limit of Planck's distribution. b) Derive the Wien distribution by taking the high-frequency limit of Planck's Distribution. Homework Equations ## u(f) = \frac {8 \pi f^2} {c^3} \frac {hf} {e^{\frac...

Hi guys, I see ferrite beads used on the input of V1 on some high end tube guitar amp designs without any indication of type and value. Can you give me some idea how to select this component and at what other places in a tube amp it could prove useful? Thanks, Billy

Hi all, I am making a frequency mixer to add together channels of an amplifier I have at 52.892kHz. I am attaching a picture of the schematic and the physical circuit I made along with the output on the oscilloscope I am measuring. Instead of the three outputs shown in the schematic, I am just...

I'm trying to remember simple probability form high school. I'd like to know how the probability of anyone event changes with frequency. So for example the probability of getting one ace of spades is 1/52; what is the probability of getting at least one ace of spades if the card is put back and...

Homework Statement For one-dimensional monatomic crystals, the dispersion plot for phonons has a maximum frequency ωmax. If a driving force oscillates the crystal beyond this frequency, the phonon will no longer propagate and will instead decay as it gets further from the external source of...

Will copper behave as a dielectric in high frequencies?...I tried to answer the question with loss tangent but relative permittivity of copper posed a problem...everyone on internet opines differently about relative permittivity of metals...then I looked at skin depth which decreases with...

I'm trying to understand the effect on a metal alloy of UV light (diode or laser) pulsing at about 1MHz. I am assuming that the stirring of atoms will generate heat, possibly moving the alloy to its eutectic point (depending on the alloy) and in particular to atomic motion. Can anyone...

Hello All, Anyone can help, but first allow me to give you some background, I have a project this project is to measure the frequency of the PCB depaneling machine that might damage the sensetive component which is the gyro-sensor. The sensor will damage if the frequency is above 75kHz or 100...

I'm looking to build a varied, high frequency power supply for a strobe light. Any suggestions on the best way to go about this? I would prefer to have it computer controlled so that I can change the frequency without manual input. Any pointers would be really appreciated! Thanks!

As I know: Velocity of sound = wavelength x frequency. If frequency increases wavelength decreases. So even if you shout loudly the velocity of sound won't change only that you will hear a louder voice. So does that mean that louder voice has higher frequency?

Hello As I read all the above links of Wikipedia about HEMT I have many problems to know better about these kinds of transistor.could you introduce me a good tutorial about HEMT transistors? Thanks

I was wondering if anyone knows the relationship with temperature and frequency tuning in wide bandgap semiconductors. I just want to know why wider bandgaps have higher temperature tolerance and why does that mean high frequencies can be achieved? Explanation with formulas would be great!

I checked some common commercial high-quality lab function generators and they seem to provide frequency output upto 50 Mhz (not a big deal), but with resolution of 1 uHz ! That means, they can generate signal with 50000000 Hz and also with 50000000.000001 Hz ?? That would equate to time-period...

I have an issue that appears to be relating to noise mitigation and grounding. Some background on myself is I have a mechanical engineering technology degree. But my job requires an ability to work with and troubleshoot electrical issues. Currently a customer is using a Servo motor on an end...

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 all, For my research I would like to create a high frequency high voltage signal. This signal should be in the order of 1kV-5kV with a frequency of around 10MHz. Can anyone help me with this? I'm not an electronic expert. I only have to apply the electric field, please note that I do not...

Hello everyone! So I am currently working on a project involving classroom equipment from PASCO. (http://www.pasco.com/prodCatalog/WA/WA-9314_microwave-optics-basic-system/#overviewTab) What I'm working on is not exactly related to the the classroom project but closely related to the...

Homework Statement Assume λ≠0. Also bypass capacitor is very large compared to coupling capacitor. a.) Draw the low frequency small signal equivalent and derive lower 3dB frequency formula. b.) Assuming transistor high frequency capacitances, draw the high frequency small signal equivalent and...

I am trying to learn GRT so I can answer questions for myself. But I might croak first, so I’ll ask here. That gravity wave interferometer they are building out in Richland, Washington - I obviously haven’t read all the technical papers on their web site, but I am pretty sure one I did read...

Please correct me if I am wrong in anything below, including clauses. i was trying to find a simple explanation for the frequency and i come up with this , 1) Frequency (Hertz(or s^-1)) = 1/ T (Seconds) F = 1/T => T (seconds) = 1/ F(s^-1) 2) "Place A" is 338 Kilometers away from "Place B"...

Hey, I wanted to generate a pulse of ON time of about 10-50 ns and time period of around 1us. Don't know how to get such precision ? Thanks

I am building a transformer of about 9.3 gain operating at 20kHz. One would think this is saturation but if that were the case there would at least be some voltage across the load. The gain of the transformer is as expected for no load conditions but I cannot get this same voltage across a load...

Hello, I have a doubt about the high frequency response of the MOSFET (or BJT as well) differential couple in the case it's polarized by a current mirror. Here's a picture of my issue (it shows the semi-differential circuit of a MOSFET differential couple with a "small" common mode ac input...

As the title suggests, how are very high frequency AC produced? A AC generator must have a limit to the rotation velocity of the coil, mustn't it? Any help would be appreciated. Thanks.

Hello All, Could you please explain what would happen if I charge a capacitor with say 30 khz DC 500 volts with a 10000 uf cap. Would a gas discharge tube, varistor, triac of 300 volts connected across the capacitor help to preventing it from exploding? Ged

I have assembeled one smps circuit for 25volts, 40 amps. Circuit gives unwanted high feaquency noise at part load. It is silent at no load. What could be the problem. I am not electronic engineer, Electronics is my hobby. Any body can help me.

Does anyone have some recommendations for MOSFET's that can be used for high frequency low current applications? The ones I found are for high current applications but my application only requires at max 20mA. Thank You.

can anyone tell me why do we use high frequency in communication? why we can't just use low frequency signal for these ?

I've read his book and he talks about AC current frequencies of incredibly high magnitudes. How was this achieved? Surely he did not just spin his dynamo really, really fast.

I understand that new findings from the 'magic' telescope, suggest that higher frequency light arrives earlier than low frequency light. The results have been taken from a light source that is very far away. apparently this shows that spacetime is not uniform and that higher frequency light...