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1
Beginners / Re: buying a oscilloscoop
« Last post by Doctorandus_P on Today at 04:20:54 pm »
I agree with the majority here.

First, not having experience with a scope and then starting with poking around in mains voltage circuits is a bad combination.

Second. EUR300 is a difficult budget. For one or two hundred euro's more you can get a very decent scope, but for EUR300 you have to accept some heavy compromise. Update / refresh rate is a lot lower, so you miss events that occur occasionally, Scopes have much less built in functions, and other compromises. What I've heard and read of both Hantek / Owon / (Uni-T too?) is that they all have silly bugs in their user interface, or some functions that are just horribly bad designed. Because I am quite sensitive to such things myself, the minimum I would buy myself are Rigol or Siglent. With those you can be pretty confident that you have a good scope, but they are just a bit above your budget.

I am a bit curious about the handheld scopes from Owon & Hantek. I recently bought an Siglent SDS1104X-E myself, but I still may buy such a handheld scope some day "just for fun". If you are interested in such a handheld device (Obvious compromises are a cramped small screen, finicky push buttons for adjustments instead of rotary knobs) then watch the reviews from Kerry Wong, where he compares features and capabilities of Owon and Hantek handheld scopes.
2
Test Equipment / Re: Choosing between entry-level 12-bit DSOs
« Last post by Fungus on Today at 04:19:57 pm »
thats unofficial hack i dont think its proper to bring it up here, ymmv. the fact still stands that GUI developer is an artist, so much wasted space that can be used for technical infomations. but its minor thing for me, i will concentrate on my subject matter ignoring artistic nature of it.

I am not sure why it would not be proper to bring up the hacks that are available? As the OP, that is one of the things I asked about early on in this thread. Obviously, different folks will have different priorities and needs, but the degree to which either of the scopes in question is hackable is definitely of interest to me. Perhaps I am not understanding what is meant by "unofficial" hack - I would have thought that any hack was, by definition, unofficial? I plead for patience, as I am no doubt further reinforcing my newbie status ...

I think he means some hacks are "official" in the sense that you enable things by installing license keys (eg. bandwidth upgrade).

I don't see why other hacks are lesser hacks though.
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The panel voltage will only go above the main source voltage if the sun is strong enough for the panel to provide *ALL* of the load current. Up to that point, the panel will provide as much current as it can at the voltage set by the AC source, which functions as a low-impedance "sink" at its voltage.

Solar panels behave strangely, and you have to keep in mind that they are basically current sources, not voltage sources. 

Below is a modified circuit which adds a schottky diode across the mosfet.  In effect, this diode takes the place of the body diode, and should be more able to handle the charge current.  When the AC source is not present, the mosfet turns on, which bypasses the extra diode as well as the body diode, and there is no voltage drop.  But even when AC is present, some current will flow through the extra diode depending on how bright the sun is.

Both schottky diodes should be 3A or whatever your maximum charge current is.  The SB220 shown in the previous reply is a 2A diode, so it wouldn't be enough.
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I just found this Chinese teardown/repair and indeed it looks like a PITA to get the power module out...
https://www.sy2k.com/2018/lecroy-waverunner-610zi-teardown-repair/
And, there's this video as well:
https://www.youtube.com/watch?app=desktop&v=q-bKj7J1fM4
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General Technical Chat / Re: Do you think an LED is a resistor?
« Last post by Sredni on Today at 04:13:06 pm »
Here

https://www.vishay.com/docs/29235/elecsimtoolkitvishaynlr.pdf

Go tell Vishay they are using an 'oxymoronic' terminology.
After all what could they know about electronic components?
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Something very strange with your MOSFET connection. It has 2 pins for Drain, so on schematic 2 pins should be short. On your schema all 4 pins connected to different circuits. I can't say who is who on Spice model - there is no pin names, only Spice node numbers
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General Technical Chat / Re: Do you think an LED is a resistor?
« Last post by BU508A on Today at 04:11:28 pm »
Do you think they are trolling?

Perhaps not, but I think, you are the troll here. At least in this thread.
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Test Equipment / Re: Choosing between entry-level 12-bit DSOs
« Last post by awakephd on Today at 04:08:52 pm »
@awakephd  So, I promised to give you a description of my experience with the Rigol DHO800 once I received it. It's been amusing to watch the Rigol and Siglent factions battle it out here, but I come from a position of total neutrality. I've had it for about a week now and I'm really enjoying it. The last time I'd regularly used a CRO was a 2-tonne Tektronix at university in the 80's. Since then, I've only worked with voltages of 132 kV and above. I've recently set up a modest home lab and I'll mostly be using it for switch mode power supply design and some audio amplifier work (I've already managed to repair two old hi-fi amps for friends). I also wanted a scope that I could easily run off a battery to float. I have a small sealed AGM deep-cycle lead acid battery that will give me around 3 hours of runtime, so with wi-fi remote control, (which works quite well), it will let me safely do a couple of odd things that I have in mind. That was one of the deciding factors that tipped me toward the Rigol, plus the unavailability of the Siglent 800X in Australia when I placed my order.

I know this is something that all modern DSOs would do, but I didn't realise just how useful the measuring functions would be. This week I've been tuning the gate drivers for an SMPS project I'm working on and it has made life so much easier. Having Vmax, rise & fall times, duty cycle, overshoot %, etc, listed to the side of the screen is fantastic. My only gripes so far are some relatively minor things with the screen design. I did a little mock-up that I'll attach below. I'm sure that Rigol will see it and address all my points in the next firmware update. ;D

1. Why do they waste the vertical space of such a small screen with all those grey borders (that I've highlighted in RED), I don't know? I guess it's from carrying the design over from their larger screen models. Anyway, it's not an issue in practice, but sure, it would be nice for the waveform window to have a little extra height.

2. I've edited the image to add the probe ratios. Why on earth haven't they put them there? Instead, the space is used to show the text "20 MHz" when you enable Bandwidth Limiting. I don't know how often people use that, but since it's an ON/OFF thing, it could easily be indicated by a symbol next to the channel number to make room for the probe ratios to be shown.

3. The 'Results' list on the right of the screen could show 8 results instead of 5 if they didn't waste all that vertical space. They could still keep the little graphic by moving it to the right of the text. It's nice that it lets you have items from different channels at the same time, so you could easily make good use of 8 quantities instead of 5. (Does the Siglent allow measurements from multiple channels at the same time? Defpoms review seemed to suggest not, I could be wrong, although it seems to allow you to display more items at once.)

4. I might like the waveform window to contract when the 'Result' list is displayed on the right since I have that displaying pretty much all the time, then again it is transparent and you can see through it. (I believe there is an option to toggle that on and off on the SDS800X).

5. I'm not sold on the idea of 'maths' traces being displayed in individual separate windows. It hasn't been a problem for me yet, but I'm guessing a scenario will come up soon where I'd like to overlay a 'maths' trace on the regular waveform traces, although you can stack the windows vertically with aligned time scales, so that's something at least.

Anyway, that's it. If I got to choose one item on the list to be implemented, it would be number 3, followed by number 5. My needs are pretty basic. I'm doing simple circuit design and just want to see what is happening. There are probably all sorts of nuanced differences in complex functionality between the SDS800X and DHO800 that I have no idea about. I'll need to do some bode plots soon, which I won't be able to automate, but having the ability to display calculated waveform peaks and phase differences between channel traces will make that a piece of cake anyway. The FFT looks good to me, at least at the frequencies I'm interested in. It seems fast enough and the accompanying table you can turn on is nice.

If the Siglent had been available, I might have got it instead. It seems to have been designed to make slightly better use of the screen real estate, whereas the Rigol looks designed to give 'wow' factor at first glance....engineers vs marketers and graphic designers, but I'm sure either would do the job for me just fine...we are really are spoiled for choice and value.

Harrow, thanks so much for circling back on this. Your first impressions are quite helpful, as it sounds like our interests are not dissimilar. I will admit that I don't typically work with 132kV ... I make it a strict policy to stay under 130kV. :)

thats unofficial hack i dont think its proper to bring it up here, ymmv. the fact still stands that GUI developer is an artist, so much wasted space that can be used for technical infomations. but its minor thing for me, i will concentrate on my subject matter ignoring artistic nature of it.

I am not sure why it would not be proper to bring up the hacks that are available? As the OP, that is one of the things I asked about early on in this thread. Obviously, different folks will have different priorities and needs, but the degree to which either of the scopes in question is hackable is definitely of interest to me. Perhaps I am not understanding what is meant by "unofficial" hack - I would have thought that any hack was, by definition, unofficial? I plead for patience, as I am no doubt further reinforcing my newbie status ...
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Test Equipment / Re: Makeshift load bank
« Last post by elevendroids on Today at 04:08:47 pm »
There's a recent video from Mr. Carlson's Lab where he used 5 industrial heaters for his 27kW load:

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