Recent Posts

1

Metrology / Re: ADR1001 - Ovenized Voltage Reference System

« Last post by Noopy on Today at 05:48:36 pm »

@Noopy: you will regret deeply your decapping of perhaps the last ADR1001 chip produced.. 

The less ADR1001 are sold the more valuable are also the pictures. 

In case of urgent need there seem to be some for sale in Ireland. The title at ebay germany is "ADR1001 Ofengesteuerter, vergrabener Zener, Präzisionsspannungsreferenz".

Interesting, these are no x-parts anymore... 

2

Projects, Designs, and Technical Stuff / Re: What FCC certification test that I need to pass for project that I am working on

« Last post by mgwalker95 on Today at 05:48:06 pm »

I tried to post it in subreddits that I thought were relevant or ones where they would think its interesting.

3

Projects, Designs, and Technical Stuff / Re: Short (1ms) high current (~200A) current pulses - relay rating?

« Last post by max_torque on Today at 05:46:44 pm »

Yup, looking to use something like a 40V bidirectional TVS (to prevent current flow when the output is connected to the DUTs normal supply voltage) and say a 10ohm power resistor (or resistor array).  Should limit peak discharge currents to 20A or so.  I'll also put  a high value discharge resistor across the caps that is permanently connected, and normally, the shut down / turn off will be handled by the control micro, that can turn off the boost converter and just wait a bit till the output cap has mostly discharged across that fixed R.  Only on the occasion where the Estop is pressed during normal test running or during supply failure (ie someones tripped over extension lead and yanked the kettle lead out the back........) will the crow bar circuit operate with the output cap charged.

4

RF, Microwave, Ham Radio / Re: Detecting very low power motion sensors

« Last post by LaserSteve on Today at 05:46:30 pm »

That picture has a plastic cased SA point blank into  an unmatched waveguide.  A bare  1n914 diode would detect a signal  at that point.  In that picture the SAs front end is massively overdriven, so it sees the harmonics in the mixer. .  The SA would not see the far weaker signal of a tiny transmitter which would  be close to or below its noise floor.

Sorry, You need a better instrument or a professional.


Steve

5

General Technical Chat / Re: Do you think an LED is a resistor?

« Last post by Sredni on Today at 05:45:58 pm »

Is a non-linear resistor, like a thermistor non-linear in at least a small signal model at a set temperature? No it's linear because "R" is constant under those conditions and not dependent on I or V.

The definition of a non-linear resistor is even broken according to the arguments here.

You don't understand the difference between small signal and large signal analysis.
You want to lock the thread because of that?
Have you seen the list if references I have given? Are they all troll (and the other names you called me)?

I assure that they, at least, understand what small signal analysis is about.

Again, I do not respond to provocations. If you don't like how Vishay classifies their components, or how experts on circuit theory call the fundamental circuital elements, just don't read this thread.

6

Projects, Designs, and Technical Stuff / Re: What FCC certification test that I need to pass for project that I am working on

« Last post by mgwalker95 on Today at 05:45:43 pm »

Thank you, I designed the custom case my self and had it CNCed at a prototype shop in china.

Thank you for pointing me in the right direction! I will look into Part 15 Class C certs!

I dont have any of the equipment, but I will look and see if I can find anyone who does pre-compliance.

7

Test Equipment / Re: LCR Impedance Viewer for Picoscope+Keysight+R&S Bode Plot Data (open source)

« Last post by Cykeltur on Today at 05:43:35 pm »

can you also state which picoscope model you are using?

Sure thing, ths a PICOSCOPE 3205A

8

RF, Microwave, Ham Radio / Re: Detecting very low power motion sensors

« Last post by glradio on Today at 05:39:33 pm »

You have a web link for the widget in question ?

Unfortunately not, otherwise everything would have been simple ...

9

Projects, Designs, and Technical Stuff / Re: Powering NeoPixels from 3.3V - Wrong but everyone does it?

« Last post by langwadt on Today at 05:38:57 pm »

Vh_min 0.7*Vdd... and 3.3V logic isn't enough for 5V Vdd

It sounds like you've misinterpreted how logic thresholds are specified.  If Vh_min is specified as a function of VDD then VDD refers to the actual voltage on the VDD pins, not the recommended typical value for VDD.  For example, if VDD was 4V then Vh_min would be 0.7*4V.

I said "for a 5V Vdd", and 5V is the most likely supply voltage

10

Beginners / Re: Replacing SRAM IC with Flash

« Last post by xvr on Today at 05:38:32 pm »

28F256 is a ancient FLASH. It's required 12V to write and very sophisticated write sequence (even with comparing to modern FLASH). So it is a very very far from SRAM.
27PC256 is OTP ROM - One Time Programmable ROM. Effectively this is EPROM for UV (Ultra Violet) erasure, but without UV window. Much more from SRAM than previous.