Questions tagged [frequency]
How many times something happens per second, measured in Hz (hertz).
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How to measure the frequency of a low frequency signal?
I am looking to measure the rpm of a wind turbine,
the wind turbine is 3-phase synchronous generator,
the frequency range I am looking to detect is between 1Hz to 60Hz,
I tried to use a frequency ...
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Why does an AC Voltage reading on a DMM decrease as the frequency is increased?
I'm doing an assignment for a lab and I've found that frequency doesn't affect the voltage reading of an oscilloscope while it does for a DMM. Online, it says this is because an oscilloscope displays ...
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Measuring electric generator AC frequency
I need to measure the AC frequency of a 230 V electric generator (gasoline powered).
I have a cheap but ok multimeter that does Hz but the reading is erratic (some 1 kHz...)
The reading on the mains ...
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Coaxial quality and frequency rating
Context
I aim to start playing with RF and the first thing I wish to do is some EMI tests.
I've been watching YouTube videos on the matter as you do, and I've seen plenty of people using SMA ...
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Clock divider/ multiplier ( 3/4, x6/4, x8/4) with CD4017s and CD4046
(UPDATED SCHEMATIC) I want to make a clock divider to add to a drum machine. I made this schematics, can anyone confirm it does what it s meant to (multiply the clock from the drum machine by 3/4,6/4,...
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Does locking a CPU frequency to a higher state (even OC) have any downsides?
I got into an argument with a friend that thinks generally is not a good idea to manually lock a CPU to a high frequency, or even overclocking by locking the frequency, in a stable scenario. His main ...
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Converter Switching Frequency
I am implementing a USB-to-system-to-battery charger (TI BQ25730 or TI BQ25723), which:
Converts USB voltage 5+ [V] to 4.2 [V] ...
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SMPS design formulas confusion
I was working on the SMPS but I have having trouble in getting a propper method to follow before designing an SMPS. I followed a video series but I didn't know where all those formulas came from as I ...
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NE555, 50% duty cycle at 110kHz
I want to get an NE555 chip with a 50% duty cycle to 108-110kHz in output.
I have already experimented with various online calculators and values. However, I never get the values that allow me to do ...
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If capacitors are frequency-dependent resistors, then what are inductors?
I was reading The Art of Electronics 3rd Edition, there it was saying "You can think of capacitors as frequency-dependent resistors."
So in terms of this description, what could inductors be?...
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unfamiliar notch filter configuration [duplicate]
This is a configuration of the notch filter that I saw in some design. It is very different from the Active Twin-T notch filter configs that show up on a quick google search. Any idea what is going on ...
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Make a tune-able resonant frequency
Using a long cable to a LC circuit reduced the resonant frequency, I reduced the inductance in order to increase the frequency; it worked. However the voltage amplitude decreased significantly. How ...
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Resonance inverters and pulsation frequency
I was reading one of the patents for the x-ray generator when I found a resonance inverter attached in front of the switching circuit. I understood how the system works but one statement written is ...
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How ideal should the clock input be for registers built out of 74HC chips?
I am a just starting my first build where a fully digital solution just isn't practical.
Basically I have an old laptop I want to give away but it doesn't have any backlight on the keyboard.
I have 2 ...
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Why don't we use the third harmonic in power transmission?
For some high power high voltage lines DC is used with the advantage that sinus wave AC obviously doesn't use the line to it's maximum capacity at all times. To correct this, we could use square wave ...
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Piezo sensor at resonance - equivalent model
piezo materials are commonly modelled with the BVD model
When the piezo is used as a sensor, they are commonly modelled as a current source in parallel with a capacitor because à external force ...
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PWM frequency for braking circuit
I am running a small DC car motor with PWM and I am using 20 kHz. This requires special op-amps with fast v/us times to get a proper square wave out to drive the MOSFETs even with drivers. I am trying ...
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Design of an antenna on a PCB card emitting between 1000 and 5000 Hz
I would like to create an antena on my PCB thanks to copper track. My antenna has to be a square like a coiled coil in order to emitt a magnetic field.
Is it possible to create an antenna like that ...
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Output load capacitance vs max input load capacitance
I am currently in the process of building a frequency divider circuit. To realize a lower frequency of 3.072 MHz. I use the: ECS-TXO-3225MV-122.8-TR
For frequency division and reduction I use D-...
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controlling power by AC frequency
I am working on circuit that will control a heat pad using a triac and microcontroller.
In order to reach minimal EMI noise rather than phase controll I am controlling the frequency.
schema:
As I ...
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Are RC /CR - Highpass filter the same?
I‘m quite new to electrical engineering and one of the tasks is to showcase and plot an CR high pass filter. I am familiar with RC HP filters but this is new to me. Just changing the order of the ...
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PVDF film to record high speed dynamic force
Do you know if TE Connectivity's PVDF films can be used as sensors for measuring high-speed impacts? The frequency range of the signal to be measured is between 3 kHz and 500 KHz. However, there is no ...
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Can we generate a frequency-dependent beams with uniform linear array?
I have some difficulties understand how can we generate frequency-dependent beams using unniform linear array. A paper that discusses this is the following: https://ieeexplore.ieee.org/stamp/stamp.jsp?...
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measuring frequency with opto-isolator
I have a circuit where 220VAC mains is stepped down by transformer to 48V and through an 5k1 resistor I'm activating optocoupler that drives a LED through a resistor on the other side. I am measuring ...
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Computation Doppler shift in ppm
I am computing Doppler shift for different flying platforms and after my first presentation, it was suggested to revise in ppm.
I compute always in Hz and have never heard even about this unit until ...
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'Best' topology to measure this weird sensor standard
I am developing an embedded solution to measure and record the analog signal from a PCB Piezotronics pressure sensor. Specifically the Model 124A21.
The sensor has some integrated circuitry to boost ...
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How does a liquid density tuning fork piezo circuit work?
I have one of these industrial liquid density meters.
I opened it in order to learn how it works, but it was very hard to reverse engineer the circuit exactly.
So far I have learned that there seem to ...
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Motor frequency increase using a VFD
If I increase motor supply frequency to 70 Hz or more using a VFD, while maintaining the voltage at its rated value, will the current drawn by the motor increase?
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Creating a large number of crystal-stabilized pulse waves at precise frequencies
I intend to generate 22 separate 50% duty cycle pulse or square waves. The frequencies range from about 5 Hz to 350000 Hz and are all irrational numbers, so I would like as much precision as possible.
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THT resistor at high frequencies
Experimenting with radio frequencies (50-150 MHz) I found that parasitic inductance of resistor can cause problems.
Reading about resistors technologies (THT) seams that the parasitic inductance of a ...
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What is the resonant frequency?
I know the formula of resonance frequency for both series and parallel circuits. But when we have a circuit that is shown in the image below where the RESISTOR and INDUCTOR are in parallel and their ...
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How can I measure the frequency of multiple square waves?
I'm trying to evaluate the frequency of 18 independent sources of square waves in my system (the signals are generated independently as feedback.) Basically, I need to have a way to use one ...
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How to debug unexpected behavior on voltage-controlled oscillator PCBA?
I designed a circuit for a voltage-controlled oscillator (VCO) for use in a synth and had it fabricated and assembled as a PCBA. I got three assemblies back and while two behave exactly to spec (and ...
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Hidden pins in Proteus
I'm implementing the following scheme and I have trouble with IC4 element (7430: 8-pin NAND) that have 7 and 14 pins, as I understand, VCC and GROUND respectively. But in Proteus 8 NAND don't have ...
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Measuring oscillator stability vs temperature
How do people measure frequency stability vs temperature? Is it by having the data of frequency vs temperature and then try to fit the curve and finding the temperature coefficient or by finding ((d(...
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STM32WL55JC1 sampling rate is different
I am using STM32Wl55JC1. STM32WL55JC microcontroller multiprotocol LPWAN dual-core 32-bit (Arm® Cortex®-M4/M0+ at 48 MHz). I am trying to do tone calculator. I am using DSP, ADC, DMA and timer for ...
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Is a 1 Hz signal the same as 1 PPS one?
Is a 1 Hz signal output from a ripple counter or divider the same as a formal "1 PPS" signal? If no, what is the difference in the time domain?
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Standards for measuring analog audio signal devices
I'm making a Analog Channel Strip for a project. I'm searching for standards that let me or give me an advice of how to measure Dynamic Range, THD and THD+N, SNR, Frequency Response and input/output ...
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Flip Flop as frequency divider precision
I am using a couple of CD4013BC as frequency dividers as per schematic :
I am checking from a data logger that they are losing some cycles, or not dividing the frequency properly from time to time. ...
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How can I change the frequency of a sine wave from 5 MHz to several smaller ones, e.g. 1kHz, 100Hz and 1Hz? [closed]
5 MHz is the frequency of the quartz based oscillator. I get a clean, sine wave output. I would like to (divide) this signal into several, lower frequencies in steps, e.g. 1kHz, 100Hz and 1Hz. I don't ...
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Resonant Frequency
simulate this circuit – Schematic created using CircuitLab
So, for series circuit to find resonance we have to have values of impedances (L and C) to be equal.
And then resonant frequency can be ...
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Decode chirping frequency with uC at center frequency of around 100kHz
Context
For my MSc project I'm building a chirping signal (a bit like LoRa) with a center frequency of 100 kHz. For now, the bandwidth is 10 kHz such that I have around 10 periods per chip. For ease, ...
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Counter showed 50Hz when I put it across my body. Why?
I was messing with my new counter when I connected it to fingers and it showed 50Hz (the AC frequency in my country.)
Why?
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RPM of a motor from frequency
I have a very old motor which I can't find any information about. I need to calculate its RPM for some work. I've attached a cog to it, held a piece of paper up to it and recorded the pitch. It was ...
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How can I measure power dissipation of a component while sweeping a square wave?
I'd like to measure the power dissipation of my MOSFET as the driving frequency changes. I have a DC (PULSE) voltage source to simulate the FET driver, and I would like to measure the FET's power ...
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VFD Driving a 40HP Inverter Rated Motor showing high Torque, Output Current at Low Speed
I am having some difficulty troubleshooting a Toshiba VFAS3-4300PC. I am using it to run a 40HP inverter rated motor that is driving a VRU Screw Compressor. I have the frequency range set for 12-60Hz. ...
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Master pitch control for oscillators
I’m doing a project of four oscillators where each one allows switching between a sawtooth or square waveform. The diagram that I attach is the corresponding one for a single oscillator, each one has ...
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LoRa - Frequency Shift Chirp Modulation - chips in a symbol
I am trying to create a form of FSCM (frequency shift chirp modulation) based on LoRa principle just to learn from it and to obtain a deeper understanding.
What I do not get:
why is (or must be?) the ...
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Why is the bitrate of infrared smaller than the bitrate of WiFi?
Infrared has a frequency of 300 GHz – 430 THz, while WiFi has a frequency of 2.4 GHz or 5 GHz.
As the frequency of infrared is greater than the frequency of WiFi, the transfer rate (bitrate) of IR ...
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Is it possible to connect an antenna of the proper length to a CPU and radiate its 4 GHz oscillating current?
Since a 4 GHz CPU has been made to provide that super high frequency, is it possible to connect an antenna of the right length to it and radiate its 4 GHz oscillating current?
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