# Questions tagged [frequency]

How many times something happens per second, measured in Hz (hertz).

198 questions with no upvoted or accepted answers
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### Sinking an input when pulses are above a certain frequency

I'd like to use a liquid flow meter of type YF-S401 at 12VDC. It produces 1.7-35k pulses per minute (rise time: 0.04us, fall time: 0.18us). I want to trigger a sinking input of a controller board if ...
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### Tips on Building An Analog VCO

I am attempting to build an analog VCO. Many of the resources I see online implement a 555 timer, but I am trying to avoid that, solely for the sake of learning how to do this in purely analog. Here ...
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### Issues associated with a single layer PCB for an RLC band pass filter

I have an issue the design of an RLC band pass filter with bandwidth ranging from 5kHz to 15 kHz. I simulated the given circuit in Proteus. It worked perfectly fine there. I then tested it on a ...
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### Generator frequency control

We are trying to run an AC generator on an RV for a customer. On an RV as you drive the engine RPM goes up and down. As I understand it, that would change the outlut AC frequency. Is there an ...
71 views

### frequency of MCP3008

I built BOOST CONVERTER, I sample the output voltage with A/D and control it using RASPBERRY Pi3, I set the switching frequency of the BOOST CONVERTER 70KHz, and the frequency of the MCP3008 1.35MHz, ...
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### How do I calculate limit frequency of the attenuator circuit?

Calculate the limit frequency $fg$ of the attenuation $v_u =\frac{ u_a} { u_e}$ at the current source I (for the value given in example), so that for $f>> fg$ exist ideal behavior. Note: ...
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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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### 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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### Frequency counter capable of measuring a range of 0 to 99 Hz

The frequency counter in Figure 2 has a range of 0 to 9 Hz and a resolution of 1 Hz. The schematic for this circuit is shown below: I'm trying to understand how this circuit works and how to increase ...
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### Hark There is an Arc

AC mains power is almost always transmitted at 50 or 60 Hz. Accepted reasoning is that lower frequencies make transformers larger and higher frequencies have greater transmission losses. ...
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### 50 Hz noise from mains plug even though it isn't connected to a power source

I am developing a front-end for a smart meter and I'm trying to measure the mains by using a power lead with the other end spliced to connect it to the front-end. I firstly powered the setup with a ...
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### DDS NBFM transmitter design

As a design exercise I'm trying to come up with a design for NBFM. I'd like to stick with digital domain as much as possible, since that's what I know best. I'm familiar with RF enough to know that I ...
107 views

### LoRa antenna frequency

I asked an antenna supplier if their 433 MHz antenna was compatible with a 433 MHz LoRa chip, and their answer was "NO". Are there any variants when it comes to antennas with the same ...
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### Phase Locked Loop Frequency Multiplier x 100

Can someone please help me with selecting resistors and caps. I have a PLL set up using a CD4046BE (PC2) connected to 2 x CD4017 decade counters to enable a x100 multiplier. My input frequency range ...
372 views

### Multimeter Always Reads 60Hz Measuring a CD4060 Pierce Oscillator

Using a CD4060 IC I’ve built a crystal oscillator circuit similar to the one in the image. I’m trying to use my klein mm400 multimeter to measure the oscillation frequency so I can get a rough ...
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### What could potentially affect some specific LoRa frequencies among others and how to mitigate it?

I have started a small LoRaWAN network. I already have setup: 1x LoRaWAN gateway (LAIRD RG186, using EU863-870); 4x T/RH Nodes (Dragino LHT65, same standard); LoRa ...
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Admittance is the reciprocal of impedance. But: 1) Susceptance is the reciprocal of reactance, or the imaginary part of admittance ? 2) Conductance is the reciprocal of resistance, or the real part ...
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### frequency response multistage

hello every one i need ask about frequency response i have an old question of our professor exam in few year, and i try to solve this question many time but i can't so please if any one have idea ...
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### Bandwidth and Carrier frequency

What is exactly the difference between the Bandwidth and the carrier frequency ? And if we have two channels with the same bandwidth but with different carrier frequency will we have different speeds ?...
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### How is it possible that lower CAS latency and lower timings on RAM memory to result in lower performance?

I have watched many benchmarks on RAM memories and I was shocked to find out that sometimes lowering the memory timings can result in lower performance in BOTH synthetic benchmarks general use of ...
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### High Frequency Pulse Rate Generator - Science Fair

( For our High School Science Fair) I am trying to find a pulse rate generator capable of producing 2.5Hz - 20,000 Hz utilize with over 10,000 LEDs all at once with several milliseconds in between ...
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### Can we use a 230 V/50 Hz solenoid on a 240 V/60 Hz supply?

My question is the inverse of this one: Can we use 220V/60Hz Solenoid on 220V/50Hz supply? The thing is that I bought a European espresso machine rated 1450-1600 W, 220-240V, 50/60 Hz and I am ...
1 vote
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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,...
1 vote
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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 ...
1 vote
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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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### Unable to measure frequency response of a Wien bridge oscillator with Bode plot

I'm unable to get the Bode plot to work with this Wien bridge oscillator circuit. Is there something wrong with my configuration, or does the Bode plot not work without an external signal source? I ...
1 vote
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### In a ZVS circuit, why does frequency increase when an arc forms?

In a GreatScott video, when he made an arc using a ZVS circuit, the frequency jumped from 40 kHz to around 80 kHz when the arc formed. I read that this is because the inductance is reduced because of ...
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### Minimum MCU clock frequency to process an analog signal with a max. frequency component of 50 kHz

An MCU requiring 4 clock cycles to process a sample has to sample an analog signal having a maximum frequency component of 50 kHz. What should be the minimum clock frequency of the MCU? This image was ...
1 vote
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### Frequency upconversion from 1 to 100 MHz for FM transmitter

I'm trying to build an FM transmitter like pifm but using the ESP32. I can generate an FM signal at the DAC output of the ESP32 with a carrier frequency of 1 MHz and a deviation of 25 kHz, but in ...
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### Converting an FM square wave into an FM waveform that is sinusoidal

How could I convert a frequency modulated square wave, like from the timer 555 output, into a frequency modulated sine wave? P.S. I added here the image of the circuit schematic for a more complete ...
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### How to increase output current while maintaining low voltage through a ferrite transformer?

I'm building a circuit to generate a 4600 Hz square wave signal and couple that signal to household 120 V, 60 Hz AC mains. This remotely turns on and off a receiver device plugged into an outlet in ...
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### Will 500 THz frequency glow antenna while radiating?

I read 700 nm wavelength is visible light, for which frequency is 429 THz. If we produce that frequency, whether antenna will be radiating visible light? Correct me if wrong.
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### What are the gain and phase margins from this Bode plot?

I thought I had a decent grip on how Bode plots work yet for this model that I am working on, I need to implement a lead or a lag compensator. A lead compensator, which I was thinking about ...
1 vote
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### CMOS Source Follower Pole Location

I have tried computing the location of the poles in a source-follower CMOS circuit. I am assuming that the gain is close to 1 of the source-follower buffer. By using the miller approximation, it seems ...
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### How do I determine the acceptable delay spread in an analog FM simulcast LMR system?

I'm using a commercial propagation analysis software to analyze a legacy VHF simulcast Land Mobile Radio (LMR) system. I'm trying to analyze the parameter "Delay Spread". The software ...
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### Why do GPU's often have a different core frequency and shader frequency?

Typically GPU's have a faster core frequency and shader frequency. Typically the shader frequency is double or more than double that of the core frequency (e.g. 607 MHz and 1215MHz for GeForce GTX 590)...
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### How does the electrical power from the output of a generator vary after a fault?

I know that after a sudden generation/load variation there is an imbalance between mechanical power and electrical power at the borders of generators which causes a frequency change according to the ...
1 vote
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### Relative error of power estimation

I'm reading my teacher code for FFT windowing in Matlab and there is one thing I don't understand. When you run the code at the end it says: ...
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### Detecting a location of the needle inside a cavity having multiple IR emitters , using IR Detector at the tip of the needle

I am working on a project where I need to find the location of a needle that has the IR detector at the tip of the needle. These needles are medical suturing needles that would help us to detect the ...
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### Why coil at high frequency pass lower current?

I am currently working on a project that uses an H-bridge to output different direction current. I use 2 P-channel MOSFETs (IRF4905), and 2 N-channel MOSFETs (IRF3710) to build my H-bridge. *reference ...
1 vote
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### PCIe 4.0 single lane frequency range

I'm looking for a connector for PCIe 4.0 testing (not a standard PCIe connector), but I'm not seeing frequency range values for PCIe, so I'm not sure what connector specs I need. Is there a good rule ...
1 vote
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### High frequency relay options for 5V 20A DC

While researching for a while upon relays, I had a hard time finding out how to choose a relay that can switch high DC currents at frequencies up to 20MHZ. I found those solid state relays, but most ...
1 vote
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### 1200W, voltage and cycle converter 220 to110

I have bought a Joule sous vide immersion circulator from USA. I want to use the device in India. I need to convert AC, 240V 50Hz to 110V 60Hz. After reading the literature on the company's website ...
1 vote
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### STM32F103C8 SPI1 clock frequency too low (~32kHz)

I am trying to program SPI1 on STM32F103C8T6 (black pill board). I have configured it as follows: ...
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### How to half frequency of triangle wave

I wanted to know if there is a method/circuit to half the frequency of a triangle wave, in the same way a flip flop can be used to half the frequency of a square wave. Any help would be appreciated ...
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### Relaxation oscilator with only transistor to measure DC voltage

I need to measure voltage from 12 to 100 volts with an MCU but with an isolated solution (so no voltage divider), my idea was to use relaxation oscillator coupled to Optocoupler in order to obtain a ...
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### Changing amperage without changing voltage

I know this has been covered before but I don't see an answer for what I want to do. Using a 12 volt car battery I want to power up a wound coil to produce a magnetic field. I would like to have a ...
1 vote
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### How to calculate the safe AC frequency at high Voltages?

If someone wanted to build some kind of machine which produces HUGE and completely safe electric arcs, how would you calculate the frequency of the AC current in relation to Volt to make it safe? Why ...
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