Recent Posts

1

Beginners / Re: Convert US standard 115V to International 230V

« Last post by Haenk on Today at 12:55:50 pm »

I assume the Meanwell PSUs are easily good enough to handle 50Hz&60Hz, and likely the filtering does not need to be super critical, otherwise one would likely find a very-highly-priced US PSU in there.

However, I'm not so sure the medical certification will still be valid when used at a different voltage - as the supply voltage is probably one of the stated test parameters (unless they do state something like "90-270V 45-65Hz supply voltage" in their certification sheet)

2

Test Equipment / Re: UTG932 testing by multiple instruments with a lot of screenshots

« Last post by bb1 on Today at 12:54:17 pm »

Here is very short Python code to send ARB waveform to UTG. As is it defines 10 sin periods in the waveform, but you can change the formula for "signal" to define any other ARB shape.  To send modulation waveform just replace "CARRier" by "MODulate". Of course, you need free Python and numpy and pyvisa packages.


import numpy as np
import pyvisa

rm = pyvisa.ResourceManager()
uniGen=rm.open_resource('USB0::yourUTGaddress::0::INSTR')

t=np.arange(0,4000,dtype=np.float64)/4000

# define waveform , here N=10 sin periods:
N=10
signal= 32767*np.array(np.sin(2*np.pi*N*t))
signal=signal.astype(np.int16)
# send to UTG
h1=b'[HEAD]:115\r\nVPP:1.000000\r\nOFFSET:0.000000\r\nCHANNEL:1\r\nRATEPOS:0.000031\r\nRATENEG:0.000031\r\nMAX:32767.000000\r\nMIN:-32767.000000\r\n[DATA]:4000\r\n'
showName='t1'   
uniGen.write(':WARB1:CARRier '+showName+' ')
uniGen.write_raw(h1+signal.tobytes())

3

Test Equipment / Re: Magnova oscilloscope

« Last post by nctnico on Today at 12:51:21 pm »

Yokogawa has / had a whole bunch of scopes which have the input & controls under the screen. So the casing is narrow & high.

Since the Magnova is basically a tablet with 4 encoders and 2 push-buttons, allowing to use a rotated screen (0 - 90 - 180 degrees) is only a matter of supporting this in software. From the description is sounds like there is a fan inside so use in a rotated position shouldn't pose a problem cooling wise.

4

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?

5

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.

6

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

7

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

8

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)

9

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.

10

Test Equipment / Re: Spectrum Analyzer - Rigol DSA815

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

Dear TV84,

thanks a million..

Regards