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Questions tagged [high-frequency]

This tag marks questions related high frequency (radio) circuits.

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MOSET keeps dying in PWM flyback high voltage circuit [closed]

I'm using a pretty simple circuit I found on YouTube. It works but not as expected. I need it running at 22-26 kHz at 10-12 V, delivering around 20 A. The IRZ44N dies at around 10 A. The most stable ...
Valerii Matviienko's user avatar
1 vote
1 answer
54 views

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. ...
Virgil_Tibbs's user avatar
1 vote
0 answers
67 views

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 ...
Rodrigo's user avatar
  • 567
0 votes
1 answer
36 views

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 ...
Nitrogen's user avatar
0 votes
1 answer
46 views

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 ...
16-bit-apps's user avatar
0 votes
1 answer
61 views

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 ...
gpowell's user avatar
0 votes
0 answers
52 views

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, ...
Hikikomori's user avatar
0 votes
2 answers
55 views

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 ...
Andromeda's user avatar
  • 473
0 votes
1 answer
98 views

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 ...
Robert's user avatar
  • 49
0 votes
1 answer
75 views

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 ...
Tremax's user avatar
  • 65
1 vote
2 answers
135 views

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 ...
Marcus Marchese's user avatar
1 vote
1 answer
63 views

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 ...
Theo's user avatar
  • 11
0 votes
0 answers
39 views

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 ...
Youssef01's user avatar
0 votes
0 answers
93 views

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 ...
Youssef01's user avatar
-1 votes
1 answer
111 views

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 ...
Aejjee's user avatar
  • 3
3 votes
3 answers
751 views

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-...
Andromeda's user avatar
  • 473
0 votes
2 answers
170 views

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 ...
mabeco's user avatar
  • 95
1 vote
2 answers
68 views

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 ...
Alessandro's user avatar
0 votes
0 answers
45 views

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?
Swapnil sawake's user avatar
0 votes
2 answers
104 views

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 ...
Luiz Oliveira's user avatar
0 votes
2 answers
64 views

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 ...
Sombercy's user avatar
4 votes
1 answer
89 views

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 (...
Alaska's user avatar
  • 101
2 votes
0 answers
87 views

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 ...
CT123's user avatar
  • 55
-1 votes
5 answers
360 views

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(...
mabeco's user avatar
  • 95
0 votes
1 answer
100 views

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 ...
Allfadern's user avatar
0 votes
2 answers
212 views

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,...
Curious Cosmopolitan's user avatar
-4 votes
2 answers
95 views

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 ...
Robert Francis Jr's user avatar
0 votes
1 answer
54 views

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 ...
Vagabond4761's user avatar
0 votes
3 answers
183 views

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 ...
Vahid Heidary's user avatar
2 votes
1 answer
228 views

Does inductance in a resistor matter if it is used as a bleeder resistor?

I am designing a Marx generator and I want to place a bleeder resistor across each capacitor in every stage of the Marx gen. I have been looking at using low cost RI80 resistors from eBay. Each stage ...
Robert Francis Jr's user avatar
2 votes
2 answers
140 views

BJT Zero-Crossing Detector for 40kHz Ultrasonic Signal - Distortion & Receiver Issues

General Information About the Project I am trying to design a zero-crossing detector circuit for convert the sinusoidal signal from an ultrasonic transducer to a square wave. Here is the image of ...
kkrgzz's user avatar
  • 121
0 votes
0 answers
108 views

Can I make a high frequency DC-DC SPMS boost converter with an SiC MOSFET?

I am trying to design a boost converter. The specifications are: Vin = 100 V Vout = 200 V Iout = 1 A Fsw = 5MHz duty cycle = 50% I tried with LTspice but some new parts do not have models, so the ...
hardstudy's user avatar
1 vote
0 answers
63 views

Arc Lighter: Relationship between transformer inductance, oscillating frequency and energy of the spark

I'm building an arc lighter using YouTube videos as a reference. This circuit from GreatScott worked for me. I'm now trying to understand the relationship between the transformer inductance and ...
selvin's user avatar
  • 11
3 votes
3 answers
318 views

Problem with push pull output

Well, I'm working on an oscillator topology to excite a piezoelectric device that works at high voltages. For this I have a high frequency signal generation stage followed by a push pull amplifier to ...
ever_pi's user avatar
  • 41
1 vote
1 answer
125 views

Problems with high frequency SPI

I have what I can best describe as an ASIC (TI's DLPC3420 digital micromirror device controller) communicating with an SPI flash (MX25L1606E). It first reads a part of the flash at low frequency of ...
DELTA12's user avatar
  • 868
0 votes
1 answer
76 views

How to amplify ultra high-frequency signal

I have found some schematics to amplify ≈100 MHz signal, but can't find a schematic for 2.4 GHz and higher, up to 5+ GHz. The main problem I face is that I can't find a transistor fast and powerful ...
AlexGenesis's user avatar
-1 votes
1 answer
252 views

How to create high frequency signal? [closed]

The question arose because I could not find a comprehensive answer, even though frequencies such as 2.4 and 5+ GHz are pretty common (bluetooth, modems, RC toys, etc.). So far, what I know is: There ...
AlexGenesis's user avatar
2 votes
0 answers
104 views

Understanding inductance and its dependency with frequency

I am trying to understand how to design an inductor that has constant parameters over a wide range of frequencies. Especially over high frequencies because I want to use them for impulse testing ...
Santi Ospina's user avatar
2 votes
1 answer
74 views

Sensor for low-amplitude, fast current pulse?

I am trying to find a way to measure low-amplitude, fast current pulses in wires ranging from ~1-5 mm in diameter, preferably using a non-contact method. The current pulses are typically around 50 mA ...
Time4Tea's user avatar
  • 123
4 votes
3 answers
540 views

Downside/tradeoffs to clamping signals with zener diodes

I have a signal source that sends fast pulsing square waves in the MHz range (encoder pulses from a motor) down a long transmission line to a receiver. I have tried many solutions and different types ...
petemoss0's user avatar
0 votes
1 answer
166 views

Please help me understand this amplitude modulation LC oscillator

I have a problem understanding the circuit below where the LC oscillator is used to produce the negative cycle wave for the amplitude modulation. I am having a difficulty in grasping the fact that the ...
kam1212's user avatar
  • 669
0 votes
3 answers
109 views

Resistor in high frequency

Can we use a simple resistor of any kind, with resistance of 1.2 kΩ in high frequency like 4 GHz?
Hamidreza Moosavie Arsenal's user avatar
8 votes
3 answers
2k views

How are RF filters constructed?

I want to know what filter circuits look like in the RF (MHz-GHz) frequency range. Are they just like low frequency LC filters, but with appropriately adjusted component values? For example the VLF-80+...
Mustafa Turhan's user avatar
2 votes
1 answer
90 views

Filtering spikes in electric fence energizer

I have designed a 12V electric fence energizer. It works as follows: A flyback converter charges a 50uF capacitor to 400V. After the capacitor has been successfully charged, a thyristor discharges the ...
Amadé Hegedüs's user avatar
1 vote
2 answers
137 views

Converting a fast-switching 0-2.5V input to TTL signal

Dear fellow engineers, I am attemping to convert a fast switching (~ns) 0V - 2.5V pulse from FPGA into a TTL-standard (0V - 5V) signal. I have been browsing for voltage regulators online. Most of them ...
Boan Fang's user avatar
0 votes
1 answer
94 views

How to switch a 200 Vpp AC signal @ 2000 Hz in under 1 millisecond?

I want to switch a ~120 V AC signal with a frequency of up to 2000 Hz. For my application (driving electrolumnescent wire) it is important that the switching duration is not higher than about one ...
Thomas Hirsch's user avatar
2 votes
1 answer
194 views

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)....
user351001's user avatar
0 votes
2 answers
49 views

What is the key circuitry in a form of high frequency signal generator that means power would be sent and reflected when there's an open load

Ive asked enough questions to explain why when there is an impedance mismatch there is power reflected which from my understanding is because there is a reflection of the waves, and also the cause of ...
George kirby's user avatar
0 votes
0 answers
36 views

On-chip Co-planar Waveguide Design on Si – SiO2 Substrate

I want to design, simulate, and fabricate on-chip Coplanar waveguides (no bottom ground) on a Silicon Dioxide layer 5um thick on a Silicon 500um thick wafer. The metal electrodes will be 1um thick ...
Ravi Pradip's user avatar
0 votes
2 answers
18 views

Debugging PLL STW81200TR not locking

I need a bit of debugging help with SWT81200 PLL that I am using on my custom designed PCB. I am able to configure registers through SPI communication, but the problem is that I am not able to achieve ...
Vasja Pira's user avatar

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