Comment summary #7
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Comment 61 ... 70
| date | article | author | comment |
| 01 feb 2020 16:24:36 | Fast Lux meter | Raymond | Hi Freddy, thanks for the circuit, i have some problems about this circuit. 1. Input voltage must be 12v DC or upper? 2. The output voltage is -3 to +3vdc? 3. What is the lux range can be measured? I want to connect the output to 3.3v MCU ADC input to display the Lux value (Camera Flash) Thank you very much. |
| 27 okt 2019 12:57:11 | Additive synthese waveform generator | LorenzB | Absolutely fantastic tool - great for explaining the basics of synthesis/analysis. Thank you very much for creating and sharing this, Freddy! |
| 25 sep 2019 23:50:36 | Additive synthese waveform generator | J\\ van de Velde | Thank you very much. Seeing and hearing go together fine now, a very good educational tool. |
| 24 sep 2019 21:35:52 | Additive synthese waveform generator | Freddy | No, you didn't use this app wrong, it was a build in feature in the wave generating software. The standard way to generate the audio waveform was to normalise the output to 1, so the signal will never be distorted. But for this application it is useful to hear the connection with the visible waveform, so i disabled the normalisation. Thanks for the usefull remark. And I tested the modification in Firefox an Chrome. Refresh the page (Ctrl+F5) if the modification isn't noticable. |
| 18 sep 2019 17:46:20 | Additive synthese waveform generator | Jan van de Velde | great applet :) I'm a physics teacher, and looking for a tool for my pupils to "get" the idea that a louder sound means higher waves (larger amplitude), and a higher tone means more waves on an oscilloscope screen. Hearing and seeing. So far I used a nice and simple (just what I need for my level of pupils) flash applet, but flash wil be phased out shortly. This generator could replace that applet, only problem is that the frequency sliders do not seem coupled to the hearable sound volume. If I up a slide I see a larger amplitude on he screen, but the sound volume in my speakers remains constant. Is there something wrong with the way I use the applet, do I overlook something, or is there, in that respect, something wrong with the applet? |
| 18 sep 2019 02:28:38 | My LeCroy recovery story | jerry1984 | i almost exist again, i can not install dso driver for my WR6050a |
| 21 mei 2019 17:05:55 | Measuring capacitance and ESR | Mykeil | Hi. Great tutorial. I found small mistake. Sin(phi) should be in a formula of Xc calculation in Method 1: Measuring capacitance. Otherwise it will not give 27.974kOhm, as written. Thank you, Regards :) |
| 09 mei 2019 11:07:46 | Measuring three-phase power | mohammed | why it is important to use the correct equipment when measuring three-phase power? |
| 04 mei 2019 12:17:45 | Extreme low voltage oscillator | Jindra | I would argue that putting two BF245A in parallel does not increase gain. Contrary to what you suggest, their transconductance (measured in mA/V) must be average of individual gm of each of the two JFETs. On the other hand, BF245A has very low drain current at Vgs = 0V (according to data sheet, between 0.5 and 2.2 mA). By putting two BF245A in parallel you increase the current and that probably enables the oscillations to start. In other words, the initial resistance between Vin and the coil is lower. You could probably achieve the same by using a single BF245B or BF245C. However, using two JFETs in parallel will allow for higher maximum drain current and power loss. I think it is a good idea. Maybe I would try 2x BF245B in parallel and look if the output improves. |
| 22 apr 2019 12:12:59 | Measuring capacitance and ESR | Freddy | Yes, it is certainly possible to determen the distance of the plates by measuring the capacitance. But be aware that the capacitance is very small: at a distance of 0.1 mm the capacitance is only 8.85 pF! 100 Hz or even 10 kHz is too low to do it reliable. Even at 1 MHz the reactance is 18 kΩ, but feasible. |