Recent Posts

1

Repair / Re: 18V/3A HY1503 PSU - weird CC/CV behavior while charging battery cells

« Last post by xavier60 on Today at 09:49:41 am »

If you plan to do the load transient test, go ahead.
If not, remove the 330pF   from across the 741's inputs. Put a 1nF capacitor or higher between its output and Inverting input.
The 10K between the Inverting input and GND must be left in place.

2

Power/Renewable Energy/EV's / Re: Automatic Solar battery charging timings based on forecast weather

« Last post by IanJ on Today at 09:48:59 am »

Wee update,

Irridiance on it's own looks like it is not enough from my testing over several different days, due to there are two irridiance values received from OpenWeatherMap.org, one for cloud based and another for clear based which has been difficult to pull into a useable figure that works for all types of weather.
So, I have changed to a hybrid calculation based on irridiance and cloud cover.

I'm pulling hourly irradiance and cloud cover data from the Meteosource API, adjusting the data pulled based on monthly sunrise/sunset as it varies through the year thus only considering the relevant hours for solar energy potential.
Then, the hourly values are are summed to create totals, then hybrid calculating a figure from both Irr & cloud which I can then use for the daily forecast SolarPV.

We'll see how this goes.......but it takes time to experience different days!

PS. I did look for another API that gives actual SolarPV predictions, but all the ones I found are very expensive. If you know of one let me know.

Ian.

3

Test Equipment / Re: New Sigrok/PulseView hardware support (Siglent SDS HD, Rigol DHO...)

« Last post by fredo_ on Today at 09:48:05 am »

Just wanted to add a hearty thanks for this.  One of the first things I tested with my new SDS804/824.  Works great!

Doing analog->digital convert->custom python decoder's direct from the scope, , is wonderful.  (Wherever it might be -- with a tailscale network, it's handy for remote investigation too.)

Thanks for the feedback @wiretail !
If you have some spare time, you might want to check the other project I'm working on: https://www.eevblog.com/forum/testgear/ngscopeclient-ultimate-acquisition-software-protocol-decoder-debug-tool/
We need testing from SDS800 owners ;-)

4

Projects, Designs, and Technical Stuff / Re: Memory - die pictures

« Last post by Noopy on Today at 09:47:58 am »

There was a U61000-SIMM! 




And here you see a U60998. Unfortunately not mine...  :'(

5

Test Equipment / Re: New Zoyi multimeter+oscilloscopes - ZT-70xS, up to 50MHz/250MSps (nov 2022)

« Last post by bebopdk on Today at 09:46:26 am »

 :-+Thanks, that did the trick...

6

Repair / Re: 18V/3A HY1503 PSU - weird CC/CV behavior while charging battery cells

« Last post by iMo on Today at 09:40:59 am »

Below the mod v5 schematics.
There is one thing which may cause the instability - the 200mA/3A switch is mounted on the front panel, shorting 4R7 for 200mA (aprox). The leads are thick, but aprox 15cm (!!) long coming to the shunt on the pcb. That may cause some HF feedback.. I will doublecheck that later on..
Ideally I planned to place a relay near the shunt with the 4R7, but there is small space for it and of course the laziness.. 

7

Test Equipment / Re: New Sigrok/PulseView hardware support (Siglent SDS HD, Rigol DHO...)

« Last post by wiretail on Today at 09:40:55 am »

Just wanted to add a hearty thanks for this.  One of the first things I tested with my new SDS804/824.  Works great!

Doing analog->digital convert->custom python decoder's direct from the scope, , is wonderful.  (Wherever it might be -- with a tailscale network, it's handy for remote investigation too.)

8

Projects, Designs, and Technical Stuff / Re: Can anyone find some information on this type of stepper motor?

« Last post by Nominal Animal on Today at 09:40:02 am »

I use LCR to measure resistance at 1K Hz
A-O--117.42 ohm
C-O--118.89 ohm
A-C--691.6 ohm；
B-M--0.266 ohm
M-D--11.835 ohm
B-D--11.903 ohm

Hmm, it seems I guessed wrong the motor pinout.

Could you redo the measurements (both resistance and inductance) between each unique pair among the six pins?  There are 15 unique pairs among 6 pins.  Then, create two tables of the measurements, one for resistance, the other for inductance, i.e.
$$\begin{array}{r|cccccc}
\Omega & 1 & 2 & 3 & 4 & 5 & 6 \\
\hline
1 &   & ? & ? & ? & ? & ? \\
2 &   &   & ? & ? & ? & ? \\
3 &   &   &   & ? & ? & ? \\
4 &   &   &   &   & ? & ? \\
5 &   &   &   &   &   & ? \\
6 &   &   &   &   &   &   \\
\end{array} \quad \begin{array}{r|cccccc}
\text{mH} & 1 & 2 & 3 & 4 & 5 & 6 \\
\hline
1 &   & ? & ? & ? & ? & ? \\
2 &   &   & ? & ? & ? & ? \\
3 &   &   &   & ? & ? & ? \\
4 &   &   &   &   & ? & ? \\
5 &   &   &   &   &   & ? \\
6 &   &   &   &   &   &   \\
\end{array}$$
I'd expect all but six pairs to have very high resistance.  Note: The resistance should be measured using DC, with a multimeter for example, not AC.

9

Buy/Sell/Wanted / Re: FS (World): Testec high voltage differential probe 70 MHz, 7 kV, 100:1, 1000:1

« Last post by Kirkhaan on Today at 09:39:45 am »

€175, anyone??

10

General Technical Chat / Re: YouTube's latest idea: server-side ad injection

« Last post by PlainName on Today at 09:39:27 am »

I wouldn't be so sure that they are failing to target you. I often go to Aliexpress to get some specific thing, and while I'm there I might browse some stuff and see something I hadn't realised I needed or wanted, or even knew existed (probably the cause of not wanting). Somehow, I come away with loads of stuff I didn't go there for.

Perhaps the 'targeting' is an attempt to get you interested in other stuff. You don't have a pet, but perhaps you'll start thinking one might be nice, and when you take the plunge you already know now where to get the pet stuff. It's the long game