Recent Posts

1

Repair / Re: HP 8566B CRT focus problem

« Last post by Greybeard on Today at 07:15:19 am »

Check all voltages at the CRT.
Check restance of all resistors and potentiometer in the focus resistor chain.

2

RF, Microwave, Ham Radio / Re: RF 2.4GHZ through Via

« Last post by uer166 on Today at 07:14:20 am »

At 2.4GHz the via is likely not the problem. That antenna layout is crap-tastic. When you say you have low Tx, did you measure it at the SMA connector conducted using a spectrum analyzer? What dBm do you expect and what did you get?

3

Test Equipment / Re: SDS800X HD - Issue disscusions - is it me, or the scope?

« Last post by eTobey on Today at 07:08:29 am »

I have setup a qualified trigger that does not trigger at all on a 100mv/div scale. The edge trigger does trigger on this signal down to 5mv. Signal is from ~0 - 2.7V

I will try to reproduce this later today. Could you please confirm one detail: I assume the critical (100 mV/div) scale applies to the channel which is the "edge trigger source", not the "qualified source" -- right?

Yes, it is the edge trigger source.

I have reproduced this issue on delay trigger too.

Edit: Would you believe it? My fridge just let the scope capture one frame (with 100mv/div), technically the trigger is working. 
(That fridge intruduces quite some EMI...)

4

Test Equipment / Re: SDS800X HD - Issue disscusions - is it me, or the scope?

« Last post by ebastler on Today at 07:04:00 am »

I have setup a qualified trigger that does not trigger at all on a 100mv/div scale. The edge trigger does trigger on this signal down to 5mv. Signal is from ~0 - 2.7V

I will try to reproduce this later today. Could you please confirm one detail: I assume the critical (100 mV/div) scale applies to the channel which is the "edge trigger source", not the "qualified source" -- right?

5

Beginners / Re: Strange noise signal on oscilloscope

« Last post by DanielDaniel on Today at 07:01:38 am »

The answer is in your other identical thread.

I'm sorry, I was under the impression that I posted this thread only once. This was a mishap. Obviously, my first posting was not finished and not ready for being published. I don't know how it got posted.

I asked the moderator to remove this thread.

6

Test Equipment / Re: Fun With Low Leakage/Bias Current: Femtompere, Electrometer, Keithley 617

« Last post by HighVoltage on Today at 06:55:06 am »

You don't place a short on the input of a transimpedance amplifier (such as an electrometer in the current measuring mode), you use a screening cap over the input (or just a bit of an aluminium foil) !

Cheers

Alex

Very true, my mind was somewhere else, thanks for pointing this out!

7

General Technical Chat / Re: Crypto currency: What are your thoughts?

« Last post by pcprogrammer on Today at 06:48:44 am »

Navigating through money stress can feel overwhelming, but it's important to remember that there are strategies and tools available to help manage financial worries effectively.

Bitcoin went high and now it is falling again.

Every single bitcoin bullrun has had a 20% drawdown before extending its leg up in a big way.

Those who can't learn from the pattern will sell out for meagre gains or a loss, those who learn it are in for much larger rewards.

Until that pattern changes due to something unforeseen and it drops even further, or never goes up again because governmental supervision took over. It is not for nothing that there is a warning for investing that results from the past are no guarantee for the future.

8

FPGA / If Lattice iCE40UltraPlus has DDR primitives like ODDR in Xilinx?

« Last post by Shell Albert on Today at 06:39:41 am »

Hi, all!   
We intend to use Lattice iCE40 UltraPlus series (ice40up5k exactly) in our low-power consumption application. We use a serial DDR external RAM (Double-Data-Rate). But I can't find if iCE40 Series support special DDR primitives like ODDR in Xilinx.  Could anyone have experience?

If iCE40UltraPlus does not support DDR primitives, the only way is to use a 2x clock frequency to operate. I sincerely get help from here.
Best regards.

9

PCB/EDA/CAD / Re: LTspice AND statement

« Last post by Shell Albert on Today at 06:33:48 am »

Haha, so interesting.  I never use LTSpice,  although it's small size and has many libraries built-in, but it's too simple.  I highly recommend you to use Cadence Pspice, powerful, complicated and popular.

10

PCB/EDA/CAD / Re: High current traces meeting small component legs

« Last post by Shell Albert on Today at 06:30:05 am »

As you know, if a IC was released on market, then it was proved to have ability to hold its rated current described in its datasheet. so don't worry about anymore,  on PCBs, an old engineer in my company suggested us to draw a big copper shape under the pin, for high current circumstances, doing the calculation is better, but for normally, we just draw a big sufficient shape because we have more space on PCBs.