Search found 3000 matches

by JR.
Sun Nov 17, 2019 7:27 pm
Forum: Pro Audio Design
Topic: Low Noise Transistors: ZTX851 versus ZTX689B Noise Performance
Replies: 8
Views: 128

Re: Low Noise Transistors: ZTX851 versus ZTX689B Noise Performance

I think, i see the trick. For low noise you need a large base emitter jonction. its all about the silicon substrate resistance. back in the bad old days a low noise design trick was to use a medium power transistor for low noise applications. The more robust base-emitter for handling higher current...
by JR.
Sun Nov 17, 2019 10:24 am
Forum: Pro Audio Design
Topic: Low Noise Transistors: ZTX851 versus ZTX689B Noise Performance
Replies: 8
Views: 128

Re: Low Noise Transistors: ZTX851 versus ZTX689B Noise Performance

I had seen this Matrix geometry but lost it and was unable to find it again. Good, I have it now. Trouble is, I do not understand it well enough. I do know the planar transistor, the manufacturing process, I do know the multiple emittors as found in TTL...But this matrix geometry is something else,...
by JR.
Sun Nov 17, 2019 10:14 am
Forum: The Peabody Lounge
Topic: They Walk Among Us
Replies: 22
Views: 1066

Re: They Walk Among Us

Now more people are at risk of metabolic disease from over eating than starving. :lol: One of the many, many reasons I don't shop at Wal*Mart. I shop at walmart because it is relatively close and has decent fresh fruits and vegetables for good prices. It's difficult to look at the scooter people sw...
by JR.
Sat Nov 16, 2019 4:59 pm
Forum: The Peabody Lounge
Topic: home improvement turns into science fair projects?
Replies: 83
Views: 4710

Re: home improvement turns into science fair projects?

took apart the USB charger... one almost dodgy (?) looking solder joint on a catch diode in the HV switcher section, but nothing else obvious. The USB charger/regulator chip is FT8371A from a chinese IC company HIENSEMI..... their webside has a pretty chinese girl wanting to chat... :lol: I found th...
by JR.
Sat Nov 16, 2019 1:35 pm
Forum: The Peabody Lounge
Topic: home improvement turns into science fair projects?
Replies: 83
Views: 4710

Re: home improvement turns into science fair projects?

The grow light turned on as programmed so that all appears sorted. 8-)

Next is the postmortem... I don't think I can put humpty back together after disassembly but I am curious to see if there is an obvious fault.

JR
by JR.
Sat Nov 16, 2019 9:08 am
Forum: The Peabody Lounge
Topic: home improvement turns into science fair projects?
Replies: 83
Views: 4710

Re: home improvement turns into science fair projects?

Initial report suggests success... the controller dongle is lighting solid blue indicating 4 hours on time programmed (still). It should turn itself on for 4 hours mid morning when I first turned it on yesterday. If it was still screwed up it would be dark or flashing on and off. Overnight was in th...
by JR.
Sat Nov 16, 2019 9:04 am
Forum: The Peabody Lounge
Topic: They Walk Among Us
Replies: 22
Views: 1066

Re: They Walk Among Us

There is a widespread and probably well meaning concern about over population, in the face of limited resources. Increasing wealth, improving childhood survival rates, and increased access to birth control can reduce birth rates in developing regions, like it already has in the wealthy developed cou...
by JR.
Fri Nov 15, 2019 12:34 pm
Forum: The Peabody Lounge
Topic: home improvement turns into science fair projects?
Replies: 83
Views: 4710

Re: home improvement turns into science fair projects?

mediatechnology wrote:
Fri Nov 15, 2019 12:20 pm
"for indoor use only"
Sometimes reads "Not for damp locations."

Good luck.
I bet it runs overnight this time.
That is my hope, but we'll see. :lol:

JR
by JR.
Fri Nov 15, 2019 11:43 am
Forum: The Peabody Lounge
Topic: home improvement turns into science fair projects?
Replies: 83
Views: 4710

Re: home improvement turns into science fair projects?

Just received my replacement USB charger so lets see if I had a personal problem with one faulty unit, or have a design problem. I notice the package for this new unit says "for indoor use only" while my laundry room is technically indoors, just not heated. It is in place and working, exposed to the...
by JR.
Fri Nov 15, 2019 11:39 am
Forum: The Peabody Lounge
Topic: They Walk Among Us
Replies: 22
Views: 1066

Re: They Walk Among Us

I do not miss playing whack a mole with hackers. Now I let Paypal worry about CC security.

Back then it was mostly russian with a scattering of US hackers hacking into my website (or trying), not obviously chinese, or north korean.

JR