Recent Posts

1

Projects, Designs, and Technical Stuff / Re: Help with DIY guitar pedal

« Last post by CaptDon on Today at 12:39:33 pm »

Holy crap, soldered by a 6 year old? There isn't much to go wrong. Probably wrecked the I.C.'s? Clean up the piss poor soldering, snip off the excess leads of the through hole components and look for solder bridges between components. There may even be shorts under the I.C. sockets. What is with all the arms and gator clips holding parts like a deco art mobile in mid air?

2

General Technical Chat / Re: Dumpster diving save VFD

« Last post by tom66 on Today at 12:37:17 pm »

I managed to save a load of 112x16 graphical Noritake VFDs from one of my former employers, they were all about to be scrapped.  Several have made their way into projects I've created.

3

Repair / Re: LG 3D 4K TV repair - UB980 range 65UB980 79UB980 84UB980

« Last post by flangefrog on Today at 12:36:29 pm »

I found the error codes for the power supply led

4

Test Equipment / Re: Standardised Way To Test Oscilloscope Screen Update Rate

« Last post by joeqsmith on Today at 12:35:25 pm »

I'm thinking about a way to come up with the best and/or most easily test screen update rate (NOT waveform update rate).
High speed camera and frame anlaysis is one way obviously.
Comments invited.

This is why I had asked to see those musical X-Y graphing tracks.   

I guess it wasn't clear but my goal wasn't to evaluate the X-Y mode of a DSO.  Rather I am trying to get a feel for how they update their screen.  Granted, its about as revealing as using an AM broadcast band radio to determine how much noise is on your supply rail.   Still, I suspect it would tell me something...  Maybe not..

Some of the new DSO's a very impressive.  My old scopes are worse than the worse ones shown in those threads.   Hard to say if it is a useful metric.


https://www.eevblog.com/forum/testgear/magnova-oscilloscope/msg5446370/#msg5446370

https://www.eevblog.com/forum/testgear/oscilloscope-music-on-dsos-post-your-results/msg5446613/#msg5446613

5

Power/Renewable Energy/EV's / Re: DIY Battery Bank from Recycled 18650

« Last post by shapirus on Today at 12:35:19 pm »

Depends on application.

(the build itself is weird regardless of application, though)

6

Projects, Designs, and Technical Stuff / Re: Build or buy? Multi-level vessel temperature logger

« Last post by voltsandjolts on Today at 12:34:30 pm »

If you're looking for a project, using optical fibre to get a distributed temperature measurement might be more interesting than multiple rtds.

7

Test Equipment / Re: Spectrum Analyzer - Rigol DSA815

« Last post by Holkly on Today at 12:31:14 pm »

Dear TV84,

thanks a million..

Regards

8

Projects, Designs, and Technical Stuff / Current Mode LED driver with different compensation circuit.

« Last post by Patrick66 on Today at 12:25:49 pm »

Hello everyone, I'm trying to study the difference in the output response when using different compensation circuits using type 1 and type 2 compensator circuits. The question is when comparing the table of type 1 compensator test C the cross-over frequency is almost similar to the type 2 compensator test A. The problem is the overshoot and time to reach stable is much longer compared to type 2 compensators even though both have the same cross-over frequency. Wanted to ask if is this considered normal or if there is some issue with my simulation. The figures of the circuit and the table for type 1 and 2 compensator circuits is shown below. Noted that the table that has 4 different test is type 1 compensation table where as the table with 6 different test is type 2 compensation table. Thank you in advance for the help.

9

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

« Last post by Fungus on Today at 12:19:53 pm »

There is no cheating. Just accept it.
It looks exactly the same if you single shot it.

What does single shot have to do with it?

You seem to be saying Rigol don't even know the basics of signal theory.

10

Projects, Designs, and Technical Stuff / Re: Homebrew Lock-In Amplifier

« Last post by RoGeorge on Today at 12:17:58 pm »

A LIA only works if you have a strong and clean reference signal, and in sync with the small and noisy signal to be measure, and only works at a constant frequency, or with very slow variations.  A LIA does not decode an unknown signal, it only averages the signal by a pattern given by the reference signal.

In regards to the max frequency, a classic LIA usually goes up to 100kHz or so, but they are very sensitive and very low noise in their analog input stage.  In contrast with that, the oscilloscope method is less sensitive, more noisy, but can work at frequencies as high as the oscilloscope can display, so virtually hundreds of MHz.  Which one to use depends of the measurement that needs to be done.

for basic experiments

For what kind of experiments do you need the LIA, what do you plan to measure with it?