Recent Posts

1

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

« Last post by 2N3055 on Today at 08:35:33 am »

There are specific posts in this thread covering most of this, but a summary doesn't hurt.

Rigol Pros: HDMI, VESA mount, WiFi built in.

Smaller size, battery option, more accessible UI, easy/neat Wifi with web/ftp access to the 'scope...

Rigol can go to 100MHz (or 125MHz) but is severely limited by its sampling rate.

Nope. Rigol can go to 280Mhz measured bandwidth, and shows signal far beyond that.

I wouldn't leave it at that bandwidth for general use but it's there if you need it and it only takes about 10 seconds to switch the model.

There's also 225MHz, 200Mhz and 125MHz options.

The lower sample rate sounds scary but when you're looking at real-life signals with probes clipped onto wires? Not so much.

(And there's no problem at all with 1 or 2 channels)

Your pointed out that advantages are telling us that it would be better as a portable multimedia device.
Switching the device BW by constantly tinkering with system apps is not same as having device that simply works.
It seems to me that people that own DHO800 Rigol scopes are buying that device to play and tinker with the scope itself, not to use it. There are also people that would buy a scope to work on their projects and want scope to simply work. To each, their own.

And again with channels. If that is your argument then fine.
But that is a 2 ch scope then.
Because with 4 ch it is not working properly.
Or 4 Ch with 70MHz.
But you cannot have it both ways.

Difference is that "the other" scope actually does work as 4ch 200MHz BW scope.
At all times, no special conditions..

So one scope is simple scope with multimedia and tinkering "built in" and the other device is serious instrument, designed to work as proper measurement instrument, with no gizmos and frills.

One is for hackers/makers and people that like to play with things, the other is inexpensive serious instrument (within obvious limits of it's class) for people that need that.

2

Beginners / Re: 555 driver and Transformer questions

« Last post by xavier60 on Today at 08:33:37 am »

The 0.1uF capacitor could be there to resonate with the primary inductance causing damped oscillations of a more controlled voltage rather than a massive narrow spike.
There could be more going on than meets the eye. Although the vibrator is mechanically tuned, it might possible that the duty-cycle is affected by battery voltage resulting in some crude regulation.

3

RF, Microwave, Ham Radio / Re: fake MPF102s from AliExpress

« Last post by shapirus on Today at 08:32:56 am »

almost all transistors on aliexpress are fake. It can be branded but remarked other type, old repackaged, or just custom made with unknown parameters.

I've noticed an interesting recent trend that the sellers started adding die pictures in the product listings like this:



I would speculate that they are still fakes, but probably of the better side of the spectrum. I'm almost tempted to get some (mosfets, I think, as they're the easiest to test for basic parameters) and see how far the fake inductry has progressed :).

4

Test Equipment / Re: Program that can log from many multimeters.

« Last post by HKJ on Today at 08:32:52 am »

Made some modifications in my Powersupply-Test and Battery-Test scripts.
No spectaculair changes, but added some checks.
Removed some small faillures.
Changed information in command window after finishing tests.

The zip file Is updated.

i found an error in the RND KEL103v2 definition.
When i tried to use the Battery Mode, TestController did not update the values, because a part of the parameters was missing in the UDP transmission.
I fixed it and the battery settings are working flawlessly now.

This will be included in the next release.

PowerSupply Test script with making BurnIn test after testing Voltage and Current depedence.
Test can be started with an Internal Resistance check.
See the graph.
First Internal resistance check.
Then Voltage - Current test.
Then BurnIn test.
In Result in Command Window.txt the results in Testcontroller Command Window.

The website Is updated.

Here are three updated definitions.

I added a few math functions to the HP / Agilent 3458A setup menu. (I needed the NULL / offset function):



Also I found a small bug in this definition. Checking my other definitions, I also found this small bug in the Racal-Dana counter definitions. So I updated those too.

All 3 will be update in next release.

5

Beginners / Re: LM317 Based Digitally Controlled Power Supply

« Last post by Zero999 on Today at 08:28:08 am »

The circuit with the LM317 as a power transistor replacement would need a negative supply for the OP-amp. Otherwise it would not work below some 1.2 V and could not limit the current with these low voltages (e.g. with a short).

Yes, you're right. I somehow messed up by copying the wrong schematic. I even said that myself.

I'll edit it.

6

Beginners / Re: Signal Edge (high and low) Validation and Counter - sharing Arduino/C++ Code

« Last post by gnif on Today at 08:26:18 am »

Duplicate post: https://www.eevblog.com/forum/microcontrollers/signal-edge-(high-and-low)-validation-and-counter-sharing-carduino-code/

I removed the duplicate, unlocking this thread.

7

General Technical Chat / Re: Relay trigger when voltage above 13v

« Last post by Zero999 on Today at 08:24:56 am »

The LM386 is an audio amplifier IC. I think you meant the LM393.

Plenty of good ideas have been given above. If you want an off the shelf solution, then you could use a voltage monitoring relay.

8

Beginners / Re: Signal Edge (high and low) Validation and Counter - sharing Arduino/C++ Code

« Last post by Halcyon on Today at 08:24:53 am »

Duplicate post: https://www.eevblog.com/forum/microcontrollers/signal-edge-(high-and-low)-validation-and-counter-sharing-carduino-code/

9

Manufacturing & Assembly / Re: Brief review of the Zhengbang ZB2520HL reflow oven (T-962A alternative)

« Last post by Kean on Today at 08:23:07 am »

Cheap IR heater ... no thanks. might be okay for some easy PCBs without special requirements. And no one can convince me that unshielded IR will be good (or good at all for components).
Conventional is much less troublesome, the next level of that seems to be Vapor Phase Soldering.

One of those IR modules probably costs around 5-7$ (just that you know what the engine of that IR heater costs). Multiply it with 4 and that's it the rest is enclosure and the controller.

I'm not sure why you post these negative comments all the time.  If you really think the cost to build, market, and support these is so small, then you should be able to make a very profitable business selling your own "perfect" design...

Most owners of these ovens seem to agree they do a fine job, much better than other cheap ovens like the Puhui range.  And not everyone has the time or tools to construct a DIY reflow oven.  I've built one using a Reflow Master controller, but the toaster oven I used is crap and I didn't want to waste more time on perfecting it.  I just use it for low temperature part drying/baking now.

10

Other Equipment & Products / Re: Pace ADS200 soldering station

« Last post by Shock on Today at 08:20:24 am »

There is a true two-channel AT420 hot tweezer with some 160 Watts. PACE has no such hot tweezer.

According to JBC they have no such hot tweezer either.

160W exceeds the DI, DDE and DME rated channel power. The DI is only 130W total, the DDE (a 2 channel station) rated 190W total, based on that alone I would not be claiming "true two-channel" or "160W" anything.