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Townies!!! I used to drive that thing all over East Anglia, in those days it wasn't as built up as it is now. Yes, those Sprinters are fast but also very bouncy on the road, Mercedes commercial vehicles are a far cry from their cars.
Microcontrollers & FPGAs / Re: how can you test a modern PSU?
« Last post by alanb on Today at 02:31:25 am »
Look at this from Mikes Electric Stuff.

 ::) Townies! The more exposed roads here in Snowdonia can have your arse twitching like a bunny's nose in high winds without plenty of weight on the back. I can't stand being in any motor driven vehicle these days, sets off my nerve pain, so any comments I make about cars are based on my sketchy memory, anyway, but I do remember that the old Merc Sprints used to be pretty rapid when light.
Microcontrollers & FPGAs / Re: how can you test a modern PSU?
« Last post by C on Today at 02:25:35 am »

 You might want to think on how to test the tester.

Here you have a shunt that you can control.

If you build two as separate things and put them in series, you could use one to test the other.

As you think of an improvement, you can test it using one against the other.
If the improvement is better, change both to match.

The power supply is a dynamic thing.
The tester is a dynamic thing.

To really know that both work properly, you need a bunch of dynamic tests.

You might think of war where you try to kill the other,
Good sensing would let you stop at the edge of the kill.

Your 20 amp power supply could be fine with a static 20 amp load yet die with 5 amp pulses at some pattern in time.

You will never know with out testing.
Eagle / Re: Eagle 9 - any thoughts?
« Last post by jgarc063 on Today at 02:24:37 am »
It looks like eagle is going in the right direction.  The routing tools are much better.    There is a key routing feature still missing:   The ability to grab a trace after a route and drag without it generating odd angle paths.     Altium will maintain the 45's, etc as you adjust the miter (as well as hug/push/shove).    Eagle would be very useful if it could do this.

Hi ehughes,

We have test builds of this feature going already. Should make it into a production release soon. Stay tuned.

Let me know if there's anything I can do for you.

Best Regards,
Jorge Garcia
I ordered and received (via Amazon Prime) an SDS1202X-E back in mid-December and was shipped the corrected 'BB' version at that time. 

Quite surprised to hear that uncorrected 'BA' versions have shown up more recently, since they clearly had good ones in the warehouse some months ago...
Beginners / OpAmp input noise and noise gain
« Last post by raff5184 on Today at 02:20:13 am »
Hi all,
few questions about op amp input noise and noise gain.

1) Given the input noise voltage n (typically in [nV/sqrt(Hz)] )  if I want to know the noise voltage in output, I calculate:
where Bw is my bandwidth and A the closed loop gain.
But what if I work only at one specific frequency f*? Is it simply n*A?

2) If n is not constant but changes with the frequency (for example see Figure 11:, and I work in the range, say from 10 Hz to 1kHz then I need to integrate the input Noise Voltage curve given in the datasheet over the operating frequency range, correct?

3) The noise gain.
The AD Tutorial (page 3: says that: "Noise gain is equal to the signal gain of a non-inverting amp. Noise gain is also the same for either an inverting or non-inverting stage. ".
So, in case I am designing an inverting op amp, by which gain do I need to multiply the noise? Non-inverting gain?

Thank you
It's totally cool, although I think if I were going to do it I'd just put the whole thing in a small FPGA, though there is something neat about "real" hardware.

The PET is simple enough that it could probably be put into the same hardware as this  I've built all the variations and it works great.
RF, Microwave, HAM Radio / Re: VHF/UHF PCB-trace simulation?
« Last post by awallin on Today at 02:18:55 am »
Version two of the 1:8 MUX board assembled today and tested.

This one is significantly better than version 1, which had deep notches at 300 and 900 MHz.

This version 2 has no major ugly things in the attenuation-spectrum up to 3GHz (max of the SA I was using).
There's a bit of waviness with a 300 MHz period and then small wiggles on top of that.
The -3dB point is around 1 GHz with attenuation of 6 to 9 dB at 2-3 GHz.

Next I want to test if this bandwidth has any effect on the rise-time of a fast pulse edge. If not, I think I am done with the MUX-design for now.

UPS can turn up late up to 7pm here. Sometimes 9am sometimes 7pm.

I love driving empty vans. They go bloody fast.
Mine did, I used to love driving it, took the twin passenger seat out and mounted it further back in the van and mounted a single seat in its place, making it into a 4 seater, paneled the floor, walls and ceiling with veneered plywood with fibreglass insulation filling the voids so it was pretty quiet for a van and fitted a banging stereo system with speakers taken from a touring coach. It went like stink that thing did, caught a lot of people by surprise when they tried to beat me away from traffic lights etc, it had so much bottom end torque that it pull away cleanly in 2nd gear and pull all the way up to a top speed of around 100mph and that was in the 80's, at that time I think it was the fastest van around. Now I think its the Volkswagen Transporter.
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