Recent Posts

1

Beginners / Re: Continuity vs Ohms

« Last post by pcprogrammer on Today at 10:18:32 am »

A continuity check is perhaps best used for nothing more involved than identifying wires in a bundle.

True, diode test is much better for fault finding.

2

Beginners / Re: Microscope for repairing phone boards

« Last post by jfiresto on Today at 10:18:28 am »

After comparing 10X to 11X, I wonder if is 11% more magnification is going to make a difference. Have you asked the repair folk at iFixit?

3

Projects, Designs, and Technical Stuff / Re: Disadvantages of Using half-wave instead of full-wave in Pure Sinewave Inverter?

« Last post by KerimF on Today at 10:15:53 am »

For commercial products, using two primary coils in the transformer is a big issue. Copper is more expensive and bulkier then FET's, so it both increases size, weight and cost.

Very true.

For a one-off or small series, this is not so much of an issue, while using simpler electronics and parts availability are more important. Especially when you live in a part of the world where electronic parts are hard to come by.

It happened that this is the situation on my side in these days. (Before March 2011, it was somehow easy to order anything from China, like power ferrite cores for efficient pure sinewave inverters, for example. And during those past golden years, I used to send just the schematics of my various designed controllers, drawn on Kicad for example. Then, the Chinese engineers drew their appropriate PCBs, by using their advanced tools, assembled the components on them and tested the finished boards before exporting them to me).

4

Microcontrollers / Re: MH-M18(clone) Bluetooth module reprogramming possible?

« Last post by Herschel on Today at 10:09:09 am »

i thought this was a dead end. pretty happy to get the actual name of the ic. is it possible to get the bluetooth firmware used in the ic?

5

PCB/EDA/CAD / Re: Ltspice is a big dissapointment !

« Last post by Zero999 on Today at 10:08:00 am »

Yes, I wish developers wouldn't change the GUI, just to appar trendy or pretend they've improved the software to encourage sales. One of the reasons why I use LibreOffice is so I can escape the crappy Ribbon interface of MS Office. Although I'm fine with the LTSpice GUI, I can sympathise, mainly because I hate MS Office.

i see you haven't installed LibreOffice 24 then

(yes, it's optional - for now. - but it's already the default)

No, I haven't.

I'm not entirely against the concept of tabbed toolbars. It's just how it has been implemented in MS Office and the fact they changed it, without the ability to go back, for no reason.

I suppose LibraOffice will have to change to make it more familiar to MS Office users. If it's bad, then I can disable it. If they make it mandatory, I can just use the older versons and no doubt it'll annoy enough people, someone will fork it and create a version with the traditional UI.

re: thread i greatly appreciated the UI revamp in the newer LTSpice 24, works much better for me, with all the changes in shortcuts and feel i never bothered making

That's how changes in the UI should be done: introduce improvements and features, without revaming everything, just because.

6

Test Equipment / Re: GW Instek GPP-4323

« Last post by Eric-H on Today at 09:59:53 am »

I saw that firmware version 1.23 is no longer available on the gwinstek site. They went back to version 1.22. However, this version also has a serious flow.

When you use the display mode that only shows the settings of one channel (mode 4) the voltage and current setpoint of channel 3 and 4 are shown incorrectly. When you first select channel 1 or 2 and then switch to channel 3 or 4, the setpoints of the previous channel are displayed! When you than activate channel 3 of 4, the output voltage does not match the displayed setpoint. E.g. the actual value shows 5V while the setpoint shows 3V (if that was the setpoint of the previous channel).

In the display mode that shows all channels, the values are shown correctly for all channels. But I prefer using the mode that shows one channel because of the larger font.

So I will continue using firmware version 1.21, that works correctly.

7

Beginners / Re: A7 (3-Pin SMD) Identity?

« Last post by Trurl on Today at 09:56:38 am »

Dang! My initial schematic was missing a trace so I'm updating it below marked in red. Also, the A7 is shown as if it were a BAV99 (though my in-circuit tests mentioned above suggest otherwise?).

8

Test Equipment / Re: Choosing between entry-level 12-bit DSOs

« Last post by 2N3055 on Today at 09:51:57 am »

"Normal Mode" means normal acquisition at siglent.
In this mode, the scope achieves up to 120000 wfs/s under certain conditions (other than specified in the data sheet).
In "Sequence Mode", which is another acquisition mode, it reaches up to over 500000 wfs/s.

Sorry if this is an ignorant question, but is "sequence mode" the same thing as "segmented memory"? (the way that R&S, Keysight, etc. define it)

The "fast segmentation" mode on some of our scopes can significantly increase waveform acquisition rate, and that's why I'm wondering if "sequence mode" is the same thing

https://youtu.be/7KoMjKwI6qw?t=462

Yes, they talk about segmented memory.
Funny enough, in Sequence menu, you set number of segments .... 

There is also always running History mode, where scope also, in a same way, also remembers all previous (to extent of available memory of course) triggered captures from normal running mode.
You can use it same as Segmented mode, except Sequence(Segmented  mode) has advantage of much faster triggering.
I believe some R&S scopes have the same feature. 

9

Repair / Re: Please help, how can I adjust this transistor?

« Last post by daisizhou on Today at 09:38:50 am »

OK。I plan to do it in 2 steps.
The first step is to buy a brand new 50V 1UF tantalum capacitor.
The second step is waiting for transportation,Since shipping takes a few days until new capacitors are received, I perform one last test to see if the fault can be reproduced and measure the resistance of the old capacitors.

Because it won't be a waste of time

10

Beginners / Re: Continuity vs Ohms

« Last post by Solder_Junkie on Today at 09:37:29 am »

From the linked manual, courtesy of CatalinaWOW, continuity is really ambiguous, I suspect they really mean below 50Ω:

"Continuity check: Provides an audible indication above 50Ω"

A continuity check is perhaps best used for nothing more involved than identifying wires in a bundle.

SJ