Search found 71 matches

by rosborne
Sat Oct 25, 2003 7:44 am
Forum: General Discussion
Topic: Cascading linear regulators
Replies: 8
Views: 1783

Re: Cascading linear regulators

cato said, >If the 3 volt regulator is powered directly from >a transformer secondary circuit,inparallel with >the 5 volt regulator, those switching currents >will be supplied by a lower impedance source and >cause fluctuations only on the input side of the >5 volt regulator, where they are less >si...
by rosborne
Sat Oct 25, 2003 7:22 am
Forum: General Discussion
Topic: Cascading linear regulators
Replies: 8
Views: 1783

Re: Cascading linear regulators

Better than having all of the regulators operating off of the 5 V supply.
by rosborne
Sat Oct 25, 2003 6:20 am
Forum: General Discussion
Topic: Cascading linear regulators
Replies: 8
Views: 1783

Cascading linear regulators

I'm building a board that has a 5 VDC input. I need 3.3, 2.5, and 1.2 and am thinking of using linear regulators. Last night it occured to me that it might be advantageous to cascade the voltages down from 5 to 3.3 then from 3.3 to 2.5 etc. The kicker is that I think this is a better way to do it, b...
by rosborne
Tue Sep 30, 2003 10:06 am
Forum: General Discussion
Topic: A grounding in electronics or tutorials
Replies: 1
Views: 543

Re: A grounding in electronics or tutorials

Fantastic site, I've been browsing it for a while and I find it to be readable, interesting, and informative. I learned things I forgot I knew and saw a couple of things put differently than I was taught that helped me understand cool stuff. We should start refering some people to these pages, inclu...
by rosborne
Wed Sep 24, 2003 11:16 am
Forum: General Discussion
Topic: physics ?
Replies: 21
Views: 3895

Re: physics ?

Thanks for the spanking dribach. I thought the heart of the question was about energy transfer. I think your description was interesting, although you are assuming that there is a down or gravity to hover in. If the energy source were great enough, and the mass large enough, and the gravity source w...
by rosborne
Wed Sep 24, 2003 6:12 am
Forum: General Discussion
Topic: physics ?
Replies: 21
Views: 3895

Re: physics ?

I think what cato says has the essence of the best answer. The frozen H2O does not have to hit air that is above 0C to melt. When the meteors hit the atmosphere miles above the surface, I'm pretty sure that the ambient temp. is below 0C. Don't forget that melting and boiling temps are dependent on a...
by rosborne
Sat Sep 20, 2003 4:47 pm
Forum: General Discussion
Topic: SN74CBT16209A
Replies: 7
Views: 1273

Re: SN74CBT16209A

"blanking" means I forgot the Phillip's part numbers, but now I remember TZA3017 and TZA3012.
by rosborne
Sat Sep 20, 2003 9:39 am
Forum: General Discussion
Topic: SN74CBT16209A
Replies: 7
Views: 1273

Re: SN74CBT16209A

I'm not thinking too much about layout, yet. I think the traces will be close to about 1". I'm going to try to keep my board size to 4"x4" and I have 2 Optical trancievers 2 100 pin quads Phillips (Blanking on PNs) Mux and Demux SerDes devices and it looks like 2 AMCC S2018 crosspoint switches. One ...
by rosborne
Fri Sep 19, 2003 3:57 pm
Forum: General Discussion
Topic: SN74CBT16209A
Replies: 7
Views: 1273

Re: SN74CBT16209A

The traces are treated as transmission lines even though the traces are short. They are differentially coupled (100 ohms P to N) and each trace is 50 ohms to ground. My setup and hold are ideally about 800 picoseconds and one inch is about 180 ps so your concern is well founded. All traces are lengt...
by rosborne
Fri Sep 19, 2003 2:21 pm
Forum: General Discussion
Topic: drill bits
Replies: 12
Views: 2370

Re: drill bits

Belay my last. Nevermind. I got it.
by rosborne
Fri Sep 19, 2003 2:07 pm
Forum: General Discussion
Topic: drill bits
Replies: 12
Views: 2370

Re: drill bits

I'm looking for # 104 and 105 size drill bits any leads. Google isn't helping me.
-Rick
by rosborne
Fri Sep 19, 2003 8:27 am
Forum: General Discussion
Topic: SN74CBT16209A
Replies: 7
Views: 1273

SN74CBT16209A

Does anyone know the operatinge frequency of of this FET Bus Exchange Switch. I'm thinking of using it, but need it to work at 669 MHz or prefferably 705 MHz. Am I just missing it on the data sheet? device data sheet I looked at TI's so called customer support and filled out a form that they promise...
by rosborne
Fri Sep 19, 2003 8:10 am
Forum: General Discussion
Topic: Back-to-back Capacitors
Replies: 12
Views: 2613

Re: Back-to-back Capacitors

Awesome links Chris. Thanks.
-Rick
by rosborne
Sat Sep 13, 2003 6:06 am
Forum: General Discussion
Topic: What microcontroller is this???
Replies: 7
Views: 1729

Re: What microcontroller is this???

Bodgy is correct. that chip could be anything. The COB packaging is the cheapest available for ICs. Most of us like to see the chip information printed on the devices we use, but that's a whole layer of expense for the chip manufacturer and the suits in charge of those operations have no trouble pas...
by rosborne
Fri Aug 29, 2003 11:11 am
Forum: General Discussion
Topic: Measuring Resistance
Replies: 15
Views: 5623

Re: Measuring Resistance

Russ is correct, I should have thought of that and the same supply is fine, but you must change the topology of the circuit. The pnp's emitters go to 9V and the collectors go to the current control resistor and the resistor under test.
-Rick