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Registered Member #135
Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735
Cool setup you got there. Now all you need are some RF voltmeters and you'll be set for life ^^
Made some progress last night with the broadband transformer coupled amplifier. Transformer predriver works pretty well from 4KHz to a few MHz, and Preamplifier works okay from 10KHz to a couple MHz, only 2 Watts out though, so I need to optimize bias and see how much power I can pull out. The Preamp is to drive another transformer which drives the PA stage, so I don't know exactly how much drive power I need, 2W or 20W.. that all depends on the gain of the PA, but that is an unknown right now. Anyway, despite the rediculous amount of hardware needed for this 2W out, it works so far.
**little update** I think I've got all the power I need. I just pushed it to over 20W, distorted, but I'll work on cleaning that up.
Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716
In the spirit of high voltage, here are some "shock" diamonds created on my workbench in 2006.
The familiar rocket-and-jet-propulsion phenomenon was discussed on 4hv in:
I had been curious to see if shock diamonds could be formed & visualized on a small scale, without combustion. Discovered that it's stupidly easy. This is a schlieren photo of an underexpanded, supersonic jet of HFC-134A refrigerant from a "canned air" spray duster. The nozzle (plastic straw) ID is 0.028 inches (0.7 mm). A more environmentally friendly source is an ordinary compressed-air blowgun, found on a hose in many workshops. A simpler way to see the diamonds is to look through the jet at a background with high-contrast edges, or look at its shadow cast by a point source (sunlight reflected by a convex mirror, or laser pointer with lens removed). Plain sunlight will do in a pinch. The shadowgraph effect changes qualitatively with distance between jet and screen.
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062
Nokia phone kludgery. Note, it sorta works, the camera glitches every so often due to crosstalk. I might be able to fix this using 1k resistors on the camera end of the cable so stay tuned...
Registered Member #902
Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042
an HDR made with QTPFSGUI, note that the noise is due to excessive electrical noise on my image sensor, one is presented without noise reduction, the other is: I think I like the noisy one better, because some traits are lost due to noise reduction
I am still new to the program, and I essentially made this in just a few minutes, so I know it's not perfect
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