Search found 865 matches

by Rich Feldman
Fri Sep 20, 2019 1:14 am
Forum: Fusor Construction & Operation (& FAQs)
Topic: What's the suitable radius for tungsten filament in making grids?
Replies: 2
Views: 98

Re: What's the suitable radius for tungsten filament in making grids?

This belongs in New User Chat area.
dnpsqh_ul.png
(41.17 KiB) Not downloaded yet
Why do you think 0.2 mm wire is too thin?
Why do you think 2.0 mm wire is too thick?
by Rich Feldman
Wed Sep 18, 2019 2:39 am
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Brute forcing high voltages with two MOTs (not what you think)
Replies: 5
Views: 164

Re: Brute forcing high voltages with two MOTs (not what you think)

p.s. We want to see your pictures. The easiest way to suit the 500 kB limit: re-take the pictures, after setting your camera pixels count to something like that of an Iphone _display_ or laptop PC _display_ , which is plenty for any forum that isn't about photography. If you're happy with existing p...
by Rich Feldman
Tue Sep 17, 2019 5:17 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Brute forcing high voltages with two MOTs (not what you think)
Replies: 5
Views: 164

Re: Brute forcing high voltages with two MOTs (not what you think)

Welcome, David. Applause for learning about coil-and-core transformer making. MOT's are, indeed, a good source of free core parts and primary windings. As you know, putting two E core blocks in series won't increase the 60 Hz volts per turn above the MOT design point, at the knee of saturation. You ...
by Rich Feldman
Thu Sep 05, 2019 11:03 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: SmCo Grid for Deuteron Deflection
Replies: 7
Views: 3407

Re: SmCo Grid for Deuteron Deflection

Let's do a SWAG without looking up any coefficients on the Internet. Rest mass of electron is about 500 keV. Proton is about 1800 times more massive (900 MeV); deuteron is twice that. Velocity of deuteron with kinetic energy of 40 keV: m * v^2 / 2 = 40/1800000 m * c^2. v^2/c^2 = 4/90000 = 1/22500 v/...
by Rich Feldman
Mon Sep 02, 2019 6:49 pm
Forum: Announcements and Site Administration Topics
Topic: Any chance of an off-topic or non-fusion forum?
Replies: 12
Views: 555

Re: Any chance of an off-topic or non-fusion forum?

One example of marginally fusion-related stuff on this forum is old threads about magnets & cyclotrons. Successful cyclotron by Chris Mullins & family, including 8-inch DIY electromagnet. With talk about p-B11 fusion as one application. Educational 3-inch electromagnet by me. Micro-cyclotrons, or at...
by Rich Feldman
Mon Sep 02, 2019 6:27 pm
Forum: Ion Gun Design and Construction (& FAQs)
Topic: Homemade Cathode Ray Tube
Replies: 6
Views: 679

Re: Homemade Cathode Ray Tube

Nice work there, Jacob. I like the Helmholtz coils and compass on the bench. About 10 years ago I played with the same sort of cold-cathode CRT. Like you, following Nyle Steiner and sparkbangbuzz. It wouldn't hurt for you to set up instruments to measure the voltage, current, and vacuum pressure. Yo...
by Rich Feldman
Thu Aug 29, 2019 6:14 pm
Forum: Announcements and Site Administration Topics
Topic: FUSOR.NET v4 is now LIVE!
Replies: 24
Views: 2116

Re: FUSOR.NET v4 is now LIVE!

Looking good so far! Thank you, thank you, thank you.

The avatar pictures and default signatures seem to have made it through. Mine is about due for a change.
by Rich Feldman
Sun Aug 11, 2019 3:55 am
Forum: Images du Jour
Topic: Hamfest booty
Replies: 10
Views: 4296

Re: Hamfest booty

Sold last month, scrounged lightly today. The guy with 12" yellow LED traffic signals was tired of selling them, and gave away the last 10 or 15. Unsurprisingly, this has a narrow viewing angle, and is very bright on axis. DSCN1555.JPG I got a box of old vacuum gauges, and a two-pipe coolant feedthr...
by Rich Feldman
Fri Aug 09, 2019 6:40 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Reforming capacitors in consumer electronics?
Replies: 5
Views: 1103

Re: Reforming capacitors in consumer electronics?

Thanks for your insights. Here's the background. Audio amp pictured in OP is one of four or five that I want to test. How much power can one deliver at well above 20 kHz? Continuously, given that their power input transformers are obviously undersized for the nominal audio output powers. I think I w...
by Rich Feldman
Thu Aug 08, 2019 2:46 am
Forum: FAQs: Neutron - Radiation Detection
Topic: FAQ - Neutron Transport Simulation, Detector Calibration, and Shielding
Replies: 10
Views: 2196

Re: FAQ - Neutron Transport Simulation, Detector Calibration, and Shielding

Thank you, Liam, for a great presentation. A few months ago I downloaded MCNP and skimmed the manual. Figured it could be an educational complement to my moderator configuration experiments. http://www.fusor.net/board/viewtopic.php?f=13&t=12649&start=10#p82995 Then had to take a break from fusor play.