9 votes
Accepted

Is it possible to change Arduino Nano sine wave frequency without using PWM?

There's no (reasonable) way to do this without changing the code on the Arduino. I have a few suggestions for you: "DDS", AKA "Direct Digital Synthesis" Some other answers have ...
  • 1,328
5 votes

Is it possible to change Arduino Nano sine wave frequency without using PWM?

To double the frequency, use every second sample in the lookup table at the same sampling frequency. To triple the frequency, use every third sample in the lookup table at the same sampling frequency. ...
  • 7,699
4 votes
Accepted

How to determine the max. frequency of the 74HC93 IC at a specific voltage?

To find values in between those given on a datasheet, use interpolation: the spreadsheet below shows how. It looks from the 74HC93 datasheet that 10 MHz should be in range, as fMAX is about 17 MHz at ...
  • 7,659
4 votes

Matrix is singular

LTspice tends to not like things having no path to ground, and the load side of the transmission line has no path to ground. You would think it's like a piece of coax and grounding one side will ...
  • 8,360
3 votes

Matrix is singular

Spice wants to produce node voltages. But as I'm sure you already know, a voltage requires two points as \$V_{_\text{AB}}=\int_{_\text{A}}^{^\text{B}}\mathscr{E}_x\:\text{d}x\$. So actually, voltages ...
  • 75.5k
3 votes

555 CMOS timer with potentiometer

That circuit is for variable duty cycle. The frequency will stay roughly the same but the ratio of high time to low time will change. Look for a variable frequency circuit, here's one you could try ...
  • 8,360
2 votes

Is it possible to change Arduino Nano sine wave frequency without using PWM?

Of course there is. Run the table entries at double speed or at half the speed for twice or half the frequency. You may want to check out DDS techniques how to generate arbitrary frequencies.
  • 105k
2 votes

Finding resonant frequency in a circuit with no inductor

Since the difference between the two RC time constants is quite large, separate answers are given for the two as a first approximation. Thus, the lower cut-off frequency will be 1 kHz, so 1/(2πR1C1). ...
  • 2,091
2 votes
Accepted

555 CMOS timer with potentiometer

I'm glad GodJihyo worked with you to produce something that makes a lot of sense. Your own comments to that answer added some important details: You are using a toggle-flop at the 555 output. That ...
  • 75.5k
2 votes
Accepted

Parasitic capacitance of high-speed comparator

Reducing R5 increases the frequency. Increasing R2 increases the frequency. You could also simulate that given that you already have a spice circuit.
  • 14.3k
2 votes

Selecting optimal phase locked loop (PLL) frequency for microcontroller peripherals

Assuming internal filter. The PLL only updates on each incoming clock cycle from the output of the pre-divider, so the lowest jitter will usually be with the lowest pre-divider value. If you don't ...
  • 65.8k
2 votes

Selecting optimal phase locked loop (PLL) frequency for microcontroller peripherals

There are multiple considerations that determine what is optimal: For the most part, a higher divider just makes your feedback path slower, so locking takes longer. An even-numbered divider has the ...
1 vote

Ferrite rod vs a whip antenna

Is a coil antenna essentially the same length of wire rapped around a rod, maybe just to make it shorter? or it works on a totally different concept? Certainly, the object of a coiled-up antenna is ...
  • 20.5k
1 vote

Ferrite rod vs a whip antenna

A ferrite rod antenna utilizes the magnetic part of the electro-magnetic radio wave to produce a received output voltage. This can then be amplified as you require Ferrites are generally good in the ...
  • 406k
1 vote

Ferrite rod vs a whip antenna

A "loopstick" antenna is more or less equivalent to a loop antenna with diameter equal to length of the rod. Because it is an electrically short antenna, it has either very low gain, or ...
  • 9,714
1 vote
Accepted

Custom frequency divider (/timer) question

You know that the dynamic range is anywhere from \$\frac{129600\:\text{s}}{12\:\text{s}}\le \alpha \le \frac{172800\:\text{s}}{8\:\text{s}}\$ or \$10800 \le \alpha \le 21600\$. In keeping with simple ...
  • 75.5k
1 vote

0 to 999 Hz frequency counter

It sounds like a timing problem with the latch and reset signals. Years ago there was an article in Popular Electronics (Feb. 1980) about CMOS counter ICs that had a simple latch/reset circuit using a ...
  • 8,360

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