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date	article	author	comment
17 okt 2021 11:10:30	Additive synthese waveform generator	antonio	very well!!! how to add other presettings for flute, viola, ...? thanks!
17 okt 2021 09:21:05	Additive synthese waveform generator	antonio	very well!!! how to add other presettings for flute, viola, ...? thanks!
03 sep 2021 14:19:49	Average & effective values	Freddy	Sorry, I completely overlooked the additional text in the sub chapter. The mistake is corrected. Thanks!
02 sep 2021 23:19:12	Average & effective values	Paul van Os	Just wanted to point out a typo 2/π instead of π/2
01 sep 2021 23:58:57	Average & effective values	Freddy	0 (zero) is the only correct value. You can check this for yourself: Measure the AC mains voltage with a multimeter placed in the DC-range . The DC-range will measure the average value. Set the multimeters voltage range manualy so it fits the peak value of the mains voltage. This to avoid damage and unsteady automatic range switching. Now you will see the multimeter measures 0 volt. The value you're referring to is the average of the absolute momentarily values of a sine wave. This is mentioned in the examples above under "Full-wave rectification sine".
30 aug 2021 00:01:39	Average & effective values	Paul van Os	Could there be a small mistake in this part: "Average value sine wave The average value of a sine-shaped voltage or current is 0. But, often in literature, the value vpkπ/2 (≈0,637vpk) is used." should read: (...), the value vpk2/π (≈0,637vpk) is used."
22 jul 2021 20:53:18	Extreme low voltage oscillator	Guy	A small update on my side: I tested roughly the same circuit but replaced the transformer with two 0805 size inductors with values of 180uH, and only used one JFET with Vgs at cutoff about 3V. It works and oscillates at up to 1.5MHz with a 22pF gate capacitor and I can adjust the frequency by replacing the capacitor or inductor. However, the circuit draws about 5mA and I wanted to lower the current. For that I will need to source higher value inductors and try again. It's quite reasonable when you think of it, when the JFET is open there is a straight path to ground through the inductor equivalent to the 'N2' winding. Also, I found that increasing the 'N1' inductance reduces the minimum supply needed for oscillation but does not reduce the overall current draw of the circuit. This proves that you really don't have to have the coupling of the windings in the transformer, discrete inductors work well. I like this inspiring small circuit. Guy Shemesh - ePiccolo Engineering
11 jul 2021 19:26:36	Magnetic circuits	Freddy	Not only the amount of energy that can be stored changes by applying an air gap: Also the magnetic resistance of the magnetic circuit increases, and with that the inductance decreases. And the product of the number of turns and saturation current increases. There is a lot going on with an air gap!
11 jul 2021 15:34:16	Magnetic circuits	Guy	Alright Freddy I accept your explanation. So this basically shows the potential in the air gap! essentially you localize the flux with the core and then force it through the air gap, at least for that small volume you have a very high energy store. Very interesting
11 jul 2021 14:41:38	Magnetic circuits	Freddy	@Guy, you are right if the field strength H where constant in every section of the magnetic circuit, but it is not. On the other hand, the flux density B is constant with some minor variations. These variation are caused by irregularities in the cross sectional areas. Especially the cross section of the airgap is affected by this. But as long the air gap length is much smaller than the width it's safe to assume an equal flux densitie in the whole circuit.