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| date | article | author | comment |
| 09 jul 2021 23:34:56 | Magnetic circuits | Talking Electronics | AIR GAP IN A MAGNETIC CORE\\ There are a number of reasons why an air gap is NEEDED in a magnetic core. \\ Suppose we have an audio amplifier with a CLASS-A output stage. This is a stage where the output is biased so that 50% of the maximum current is flowing when the amplifier is at rest and the output device (such as a transistor) is turned on MORE during part of the cycle and turned on LESS for the other part of the cycle to produce a sinewave. \\ Because 50% current is flowing during QUIESCENT conditions, this current could quite easily be sufficient to fully saturate the magnetic core, so that when the transistor turns on MORE, the magnetic core cannot accept the increased magnetic flux. \\ The answer is to add an air gap by using sheets of paper between the stack of "E" pieces and "I" pieces where the end faces of the E laminations meet the I laminations. \\ What you do is simply add thin sheets of paper and deliver a sinewave to the transformer and use a CRO to detect the best output (without any clipping).\\ In other words, an air gap is used to eliminate the effects of DC SATURATION. |
| 09 jul 2021 21:48:39 | Magnetic circuits | Guy | Can you please elaborate more about the air gap in a magnetic core - what is it used for? Is this for transformer application or sensor application? Thanks |
| 09 jul 2021 21:38:38 | Oscilloscope probes | Guy | Regarding the current probe, you said that the current in the primary wire will magnetize the core. I can understand this for AC current but what about DC current? Maxwell's equations always talk about the derivative of the magnetic flux as a source for electronic potential, so how it is working with DC current (i.e derivative is zero)? |
| 02 jul 2021 08:32:51 | Extreme low voltage oscillator | Guy | I know the Hartley oscillator has many variations. I like this variation in which the usage is with a JFET, meaning that Vgs = 0 is an 'always on' position, giving opportunity to a very low voltage oscillations. I do refrain from the transformer though, since its big and costly. Also, its DC resistance is likely to vary the frequency. Have you tried to design the feedback using smt components, such as coils and capacitor? |
| 26 apr 2021 11:47:57 | Arduino wattmeter | Jose Carlos | Hello. This program is designed to run on the Arduino Nano. My question is if it can also work with the new Arduino Nano Every without any modifications. And if necessary, what would those modifications be? Thanks. |
| 05 maa 2021 18:24:32 | Additive synthese waveform generator | Jon | In Safari, the frequency only works right when the page is first loaded. I can change the frequency once. Changes to frequency after that point are ignored. Thank you for this tool. It's great for demonstration purposes. |
| 21 jan 2021 12:55:20 | Additive synthese waveform generator | Freddy | I don't know of an online instrument. But I think a midi keyboard with a Hammond organ simulation will do the trick. |
| 18 jan 2021 17:11:44 | Additive synthese waveform generator | Some user out there | As someone with absolute pitch, this is a very interesting conept to me, I must say. It made me think if you know a website or application out there where you could make your own instruments like this, where you could customize each overtone from the first to however many it takes to get to 20,000 hertz. I am more into music than I am into programming, so that is why I am asking this through a more musical perspective. If you do not have an answer, that is completely fine. |
| 09 dec 2020 20:16:13 | Arduino wattmeter | Janjos | Hi, I adapted the Arduino watt meter code so it runs on a UNO. For those that want to try it before building it, the code can also be tested using SimulIDE (www.simulide.com), together with a ready to use simulation circuit that I draw. Am I allowed to post both files, .ino and .simu, here ? If yes how ? Best wishes, Janjos |
| 30 nov 2020 16:03:07 | Fast Lux meter | Freddy | Yes, the BPW34 is more sensitive, but its spectrum lays more in the near infrared region and does not represents the human eye. |