Activity for coquelicotâ€
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Edit | Post #281059 | Initial revision | — | over 3 years ago |
| Question | — |
How building a follower satisfying rather extreme requirements. What is your best suggestion for building a follower that would ideally satisfy the following spec: frequency: from 100 Hz (or lower) to 1 GHz input signal impedance: 1 Mohm input signal amplitude: from 1 mV to 1V at least output load to be driven: 50 Ohm. The follower need not be absolut... (more) |
— | over 3 years ago |
| Comment | Post #280921 |
You should not connect the output for S11. For S21, you have to connect both terminals, but again, be careful to protect the VNA. (more) |
— | over 3 years ago |
| Edit | Post #280921 |
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— | over 3 years ago |
| Edit | Post #280921 | Initial revision | — | over 3 years ago |
| Answer | — |
A: Measuring Input/Output Impedance with a VNA The input and output impedance of these amplifier is 50 Ohm. You don't need to measure them. That's because they are intentionally matched to the characteristic impedance of the coaxial cables that connect to their SMA connector, which is always 50 Ohm for most microwave devices, except television ... (more) |
— | over 3 years ago |
| Comment | Post #280873 |
@Olin Lathrop. Thx for your answer. That's not me on the video, it's just a video showing the same GDO as mine, where the "emitter" function is used. I think you have rather described the "oscillating detector operation" of the dip meter. The "absorption wavemeter" is something simpler (https://en.wi... (more) |
— | almost 4 years ago |
| Edit | Post #280870 |
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— | almost 4 years ago |
| Comment | Post #280870 |
@Olin Lathrop. A grid dip is a very well known device from the past, that is still used by radio ham. Google@grid dip to see tremendously many entries. I am not supposed to write an article here, sorry. Yet, since you say the question is unclear, I have added what I think that should be added to mak... (more) |
— | almost 4 years ago |
| Edit | Post #280870 |
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— | almost 4 years ago |
| Comment | Post #280870 |
@Olin Lathrop. I've added a link to the full documentation where everything could be seen. I have to go work, but later, I will add pictures if necessary. (more) |
— | almost 4 years ago |
| Edit | Post #280870 |
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— | almost 4 years ago |
| Edit | Post #280870 |
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— | almost 4 years ago |
| Edit | Post #280870 |
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— | almost 4 years ago |
| Edit | Post #280870 |
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— | almost 4 years ago |
| Edit | Post #280870 | Initial revision | — | almost 4 years ago |
| Question | — |
My grid dip: how does this electron tube technology work? Here is a video of the AN/PRM10, and here is a schematic (I believe the image can be zoomed): an/prm10 As most commercial grid dip meters produced in the past, this one possesses several functions in addition to the grid dip function. One of these is the "absorption type wavemeter", that ... (more) |
— | almost 4 years ago |
| Comment | Post #280714 |
@Olin Lathrop. Thank you for this nice answer. I would like to precise my understanding (I don't think this is worthy a new question since the answer may be more or less "yes" or "no"). So, a measurement with a standard probe could be seen as the juxtaposition of a DC measurement with respect to the... (more) |
— | almost 4 years ago |
| Edit | Post #280713 |
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— | almost 4 years ago |
| Edit | Post #280713 |
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— | almost 4 years ago |
| Edit | Post #280713 | Initial revision | — | almost 4 years ago |
| Question | — |
Is it always necessary to use the ground terminal of the oscilloscope probe? Assume my oscilloscope is grounded, and the DUT is grounded as well (earth ground). I am using a standard 10 Mohm impedance 1:10 passive probe. So, the ground terminal of the probe is in fact connected to earth through the oscilloscope chassis. Is there any reason to connect the ground tip of t... (more) |
— | almost 4 years ago |
| Comment | Post #280672 |
Have you think about making a stupid current source by hand: jfet + resistor, or npn + resistor + zener ? (more) |
— | almost 4 years ago |
| Comment | Post #280578 |
Of course, this is a stupid diode in the other direction, but that's not what is needed in general for AC circuit (otherwise, use a diode). (more) |
— | almost 4 years ago |
| Edit | Post #280578 | Initial revision | — | almost 4 years ago |
| Answer | — |
A: MOV vs. TVS diode MOV are bidirectional components suitable for both AC and DC circuits, TVS are most often unidirectional, despite bidirectional TVS are also available; conducts more current compared to TVS diodes (in general); dissipates energy in a solid material and not in a junction. I would use a MOV whe... (more) |
— | almost 4 years ago |
| Edit | Post #280152 |
Post edited: Formulas in Latex + a slight simplification of the (2/25)/ (f_stop/f_start)^2 formula |
— | almost 4 years ago |
| Suggested Edit | Post #280152 |
Suggested edit: Formulas in Latex + a slight simplification of the (2/25)/ (f_stop/f_start)^2 formula (more) |
helpful | almost 4 years ago |
| Comment | Post #280152 |
Nice! a digital heterodyne! I much like this idea (+1). I will suggest you an edit for the Latex formula. Note: it's very easy to learn basic Tex/Latex typesetting (1h at most), and that's very useful in many circumstances and sites. (more) |
— | almost 4 years ago |
| Comment | Post #280152 |
That seems to be an interesting trick. But I don't understand how a XOR can produce a triangle wave. According to my very limited knowledge of digital electronics, there is a low and high state. How does that produce the intermediate states of the triangle wave? or are you using the RC network to thi... (more) |
— | almost 4 years ago |
| Edit | Post #280132 |
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— | almost 4 years ago |
| Edit | Post #280132 | Initial revision | — | almost 4 years ago |
| Answer | — |
A: ESD USB Shield Connection & Filtering >It's kind of surprising that the TVS diodes dumping ESD into the GND plane don't affect the microcontroller; however, if the shield dumps ESD into the GND plane it has a very strong effect. That's what makes me think that the answer of Nick Alexeev is very relevant: the TVS diode has a small capa... (more) |
— | almost 4 years ago |
| Edit | Post #280117 |
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— | almost 4 years ago |
| Edit | Post #280117 |
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— | almost 4 years ago |
| Edit | Post #280117 |
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— | almost 4 years ago |
| Edit | Post #280117 |
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— | almost 4 years ago |
| Edit | Post #280117 | Initial revision | — | almost 4 years ago |
| Answer | — |
A: Confused about the amplitude and shape of output voltage pulse You haven't explicitly stated what is the voltage supply at the anode of the LED, but according to your schematic, it is apparently 3.3V. So, I'll assume this value in what follows. There is a flaw in you logic: Whenever the PWM signal is high, the mosfet is conducting (ON state) and the volta... (more) |
— | almost 4 years ago |
| Edit | Post #279969 |
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— | almost 4 years ago |
| Edit | Post #279969 |
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— | almost 4 years ago |
| Edit | Post #279969 |
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— | almost 4 years ago |
| Edit | Post #279969 | Initial revision | — | almost 4 years ago |
| Answer | — |
A: Driving ADC with opamp with large rails Here is a solution to protects very well the ADC from over-voltage spikes, avoid any simulation and design consideration, and that also protects the ADC from a possible negative output spike from the op-amp output at startup. protectADC For high frequencies, it may be necessary to put a "compen... (more) |
— | almost 4 years ago |
| Comment | Post #279966 |
@Olin. Your answer is again fascinating: 1. why may the modest resistor inside the loop lead to instability? and 2. (probably related) could you explain how the cap solve this problem (I've never seen this technique). If the cap were connected after the resistor, I would say it improves the high freq... (more) |
— | almost 4 years ago |
| Comment | Post #278933 |
For example, regulating the voltage with the battery as a voltage reference is bad in general, and using the base of the transistor to pass the backup current is bad design as well. Also, charging the battery this way is bad. At the price of few basic added components, you can do everything right. Yo... (more) |
— | almost 4 years ago |
| Comment | Post #278933 |
@circuit fantasist. That means a man building things not rigorously, in order for it to work in the given case, but not according the EE rules of the art. A good electric engineer would never have done that this way. /continued (more) |
— | almost 4 years ago |
| Comment | Post #279733 |
Well, you asked as if there a superior architecture approach, so I answered to that. (more) |
— | almost 4 years ago |
| Edit | Post #279733 |
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— | almost 4 years ago |
| Edit | Post #279733 | Initial revision | — | almost 4 years ago |