Questions tagged [high-frequency]
This tag marks questions related high frequency (radio) circuits.
541
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Design for a Peak Follower for 3-30MHz? [closed]
Anyone have suggestions for a broadband (3-30MHz) peak detector? So far I'm working with high-speed op amps such as LMH6628 and AD8092, using a ceramic capacitor to hold the peak charge and a resistor ...
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2
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Litz Limitations
Litz wire is very old, perhaps 100 years. It was used and still is used on Medium Wave ferrite rod antenna coils. The thinner the wire is the better things are at higher frequencies but more strands ...
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Protection from high voltage in high frequency ignition in plasma cutting machines
I am currently in the process of designing a circuit for detection of a short circuit of a plasma cutter nozzle with material when there is no arc. The important requirement is that detection ...
CommunityBot
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2
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What type of amplifier circuit do I need to drive a piezoelectric ultrasound transducer?
I would like to drive the following piezoelectric transducers at 200 V or their maximum voltage (60-1000 V):
https://www.manorshi.com/16mm-Dog-Repellent-Ultrasonic-Transducer-25khz-Detect-Sensor-...
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100 kHz PWM motor driver PCB/cable considerations
I am designing a board to drive a DC micromotor which requires a 100 kHz PWM signal. The board is mainly a digital design board, with very little analog signalling.
I am planning on driving the motor ...
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A redesign of a bulky 12 kV source
I’m a low voltage electrical prototype designer. Currently I’m working with a client that had a circuit that transforms 240 VAC (50Hz) to around 2400 V. After that they use a Cockcroft Walton ladder ...
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Are there any effects on capacitance and inductance when operating at audio-frequency (i.e. 1kHz - 20kHz)?
At the moment, I study something about audio-frequency track circuits for railway applications and to understand its operation, an accurate model of such a circuit is required.
The circuit of audio-...
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158
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High frequency voltage divider circuit, capacitor placement to lower ESL (is this a thing?)
I have a divider circuit similar to a x10 scope probe.
I need a bandwidth of least 100MHz, preferably greater.
I am using through-hole MICA capacitors (1%).
The capacitors have a low enough ESL that ...
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1
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1
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Wideband Photodiode Amplifier (>= 50MHz) and Obnoxiously Big Input Bias Currents of Current Feedback Amplifiers
I'm toying with the idea of building a >50MHz Bandwidth Photodiode Amplifier, built around a 1GHz AD8009ARZ Current Feedback Amplifier. I got two photodiodes that have a bandwidth exceeding 1GHz.
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How can I find out if High Frequency Injection (HFI) is being used in a Sensorless BLDC motor?
I have a small BLDC sensorless motor that runs at 34 V DC, reaches 40K RPM, has low resistance(5 ohms) between its phases.
Its own driver manages to run this motor at really low speeds, 1K RPM, at ...
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3
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Opto-coupler base connection speed influence
I am using a 4N25 opto-coupler for 5kHz to 10kHz application. In some datasheets the turn on and turn off times are mentioned to be 3us. I am wondering if this opto-coupler is suitable for my circuit'...
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Why is the frequency response from my 1X and 10X probe seem to be converging with increasing frequency?
I'm a Mechanical Engineer trying to get into electronics so please excuse my lack of understanding.
I'm feeding a 5.0 Vpp sine wave into my SDS 1202X-E scope from my signal generator (see image below)....
CommunityBot
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3
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Distortion in output signal in amplifier after connecting load
I want to design an amplifier which works in 20kHz-100kHz range with 0.1V peak to peak signal.
This is my circuit.
It works fine in the simulation. It works fine without connecting R6 8 ohm load. But ...
CommunityBot
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3
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How do I add a DC offset to my RF signal for a 50 Ohm Device?
I'm working with a system that requires a ~250-400 MHz modulation signal from 0 to 1.5 V (or -1.5 to 0 V) on an electro-optic modulator (EOM, Jenoptik AM635). I have a signal generator capable of ...
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Simplest way to interface a high-speed (125 Msps) ADC: FIFO, RAM, SerDes or FPGA
I have a 1.8 V, 125 Msps ADC (ADS4125) with an output of 12-bit parallel LVDS or CMOS. The system is operating in bursts: the data is sampled for 8 - 30 us, with a 100 ms wait time in between. I need ...
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Troubleshooting my DIY Tesla coil setup
Firstly let me say I'm relatively new to HV, so apologies for any silly mistakes. I made a Slayer Exciter circuit, powerful enough to drive a flyback transformer and make 3mm sparks. The circuit is ...
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power supply for small volume plasma
I need to power a small plasma source (about 1 1/2 inches internal diameter) with a single
wire like anode. The target pressure range is up to a couple of hundred millitorr.
I have been looking at ...
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184
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Problem with calculating high frequency response of a CE amp
I have this amp:
The parameters of the transistor are hfe=120, Cje=40pF and Cjc=4pF. I am also told to assume Cpi = Cje = 40pF and Cmu = Cjc= 4 pF.
From that I should calculate fh and compare it ...
CommunityBot
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How to calculate reduction of inductance eddy currents in ferromagnetic core?
Suppose you have a LC circuit. Now at high frequency the core loss of the inductor meaning hysteresis and eddy current loss will increase. When this happens the frequency increases while the ...
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How to make prototype circuits that include microcontrollers, and avoid breadboard annoyances at high frequencies?
From my searches of the web ( as well as this question ), I have found that breadboards - like the one on picture - aren't a good idea when your application involves high frequencies.
I am going to ...
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Generate 200MHz Phase-Shifted Voltage Sine Waves
I'm looking into a way to construct a circuit that can generate ~200MHz negative voltage sine waves (8 channels), where there is 11 degrees of phase offset between the channels (0 deg, 11 deg, 22 deg, ...
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Using transfer via in PCB
From which frequency we need to consider a transfer via, when there is a transition of a signal on different layer in a PCB? higher than 1GHz? I need to know the threshold for considering these types ...
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How can I measure a 100 MHz signal with unknown source impedance with an oscilloscope?
As a part of a device I designed, I have to measure multiple higher frequency square wave (and sinusodial) signals with unkown source impedance. The intended signal path is shown in the picture:
My ...
- 171k
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Match 50 ohm impedance to LNA input impedance
I have following PCB version of circuit: on SMA input we have antenna strictly matched to 50 ohm, then we have regular RF switch IC, after RF switch impedance matching network and final stage is ...
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How to use this crystal oscillator? [closed]
I recently bought a 315Mhz crystal oscillator off of Amazon but I can’t figure out how to use it nor can I find any information online about it.
The only thing I can find on them is that picture.
I ...
- 19k
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AD8611 comparator at 60 MHz
I'm trying to process a sinusoidal signal into a square wave at frequencies above 1 MHz. This is my first time doing this so it doesn't work properly. If anyone can help with an explanation, I would ...
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Advice on using limiters for circuit protection in HF circuit [closed]
I am designing a receiver amplification circuit and I'd like some advice. We operate in the 10-20 MHz range, and in proper operation receive input signals on the order of -35 dBm. Our current RF chain ...
- 664
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High magnetic permeability material at 100MHz
I'm doing experiments as a hobby and was trying to find a material with good (very good) magnetic permeability at least at 100 MHz (higher frequencies are even better). Ideally the material would have ...
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High frequency gate signalling from TLP 250
I am trying to work with MOSFET 10n60 at high frequency but the gate to source output and the drain to source is not right at high frequency.Blue signal is drain to source and yellow signal is gate to ...
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20 kHz full bridge inverter
I have designed high frequency full bridge inverter 20 kHz. I am using TLP250 as my gate driver and 10N60 MOSFETS. The problem is that it works fine at frequencies up to 2 kHz.
At high frequency the ...
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How to use the AD829 Op-Amp? (Weird "auto" output)
I have an AD829 Op-Amp, which I have tested in LTSpice with this circuit/output:
In this simulation I'm amplifying a 6mV signal at 110MHz with the AD829. I have tried this circuit on a breadboard ...
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Measuring the quality factor RLC circuit
I am trying to get the Q factor for this circuit but I don't know how to simulate it properly.
I did a frequency sweep from 1 Hz - 30 MHz.
The oscillating frequency is 16 MHz.
I can't get the ...
CommunityBot
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3
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Return current on PCB
As PCB designers we all know that for high frequency signal (MHz), we should design return path (reference GND plane) underneath the signal as follows:
https://www.allaboutcircuits.com/technical-...
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Cable current rating for high frequency applications
I am looking for power cables for high-speed motors, with frequencies up to 700Hz. All the tables that I find online are referred to 50/60Hz applications. I am not able to find derating factors ...
- 43.2k
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What is minimum gain crossover frequency in bode analysis?
I know gain crossover frequency at which magnitude of open loop transfer function is 0. But what is the case here for minimum Wgc?
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Will the antenna be detuned by the presence of the MHF3 plug in parallel?
This is a design question. Below is the layout of a project that involves some features, including an ESP32 circuit and its antenna:
The part of the schematic related to both images is:
THE PROBLEM: ...
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805
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Measurement of transformer with a vector network analyser (VNA)
I have a planar air core (no ferrite) transformer in a PCB. I need to characterize the transfer function of this transformer from DC to 500 MHz using a vector network analyser (VNA).
My first ...
CommunityBot
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How to create a frequency-dependent device with low losses at 50/60 Hz and high losses at 100 kHz
I'm working on a device to dampen high-frequency transients. Here are the specifications:
Rated current: 30 A RMS
Losses at low frequency (50/60 Hz): <10 W (required steady-state condition)
Losses ...
- 22.7k
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Switching circuit with logic 3.3V control on p-channel JFET
The task is to derive sinewave (of higher frequency) chopped by step-function (also periodic but of lower frequency, i.e. several periods of sine wave are placed in that pulse). So I have a sinewave ...
4
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Why is the core resistance modeled as 2*Rp and capacitance as Cp/2 in a common-mode choke?
I directed my attention to a paper regarding the modeling of common-mode chokes. Within this paper, the authors structured the circuit in such a manner that they designated the core resistance (...
- 1,316
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High Speed Signal on Large Circular Ring
It's frequently communicated that when working with signals in the Ghz range, routing is extremely important to signal integrity. Pretty much any inclusion of unnecessary stubs is out of the question, ...
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Conductivity and high speed transmission using aluminium slip rings
So I came across a Persistence of Vision globe based video where a YouTuber he makes DIY slip rings to power and control some LEDs as seen in this picture:
My question is, given the high rate of data ...
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How to achieve 50 Ohm Impedance with a SMB connector
I have a PCB design with a SMB connector but can't find any information about how I should treat the pad to ensure 50R impedance.
Should there be a keepout on the ground layer directly beneath this ...
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5
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365
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Sine oscillator at extremely high frequencies
I would like to make a "good" (doesn't need to be perfect) sine wave oscillator from 50 GHz to 1 THz, if possible with two outputs: one is \$\sin(2 \pi f t)\$, the other one would be \$\cos(...
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4 MHz RF-receiver not working
I have been trying to make a 4 MHz receiver, to receive a ASK/OOK modulated signal but it never really works. I have my suspicions that it's the LC tank that is not tuned correctly, I am quite new to ...
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Intuitive explanation of open stub behaviour
Can someone please give me an intuitive explanation of open stubs?
I have the length-based mathematical derivation and explanation from my textbook, but I am looking for an intuitive one.
For example,...
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What are the Best Methods for Creating Pulsed DC or AC Current at 2.4 - 2.5 GHz Frequency Range?
Some of you may be aware that UFOs are sometimes recorded emitting microwave radiation. I think they might be using an electromagnetic coil that is being pulsed with DC current or is using AC current ...
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Multisim simulation of a current division
I'm currently trying to simulate a current division for three transmission lines that are in parallel (but all of different lengths). I want to study how the current divide itself as we progressively ...
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Purpose of Carrier Detect (CD) pin in RF modules
I have a RX2-433-160-3V receiver module from Radiometrix. I wanted to know what the purpose of the CD pin is. I have read the datasheet but don't really understand what it's meant to do. The datasheet ...
- 151k
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3
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219
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How to get megahertz frequency with a 555?
I need to produce a 1.7 MHz signal. Up to around 200 kHz the 555 IC and my simple astable circuit are working just fine as expected, but when I decrease R1 and R2 to less than 100 Ω the frequency ...
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