Search found 12 matches

by Forrest Mims III
Sat Jan 31, 2009 7:23 am
Forum: General Discussion
Topic: memristors?
Replies: 38
Views: 6587

Re: memristors?

Analog memory technology bears close watching, for it can revolutionize analog computer technology. The new methods are much more sophisticated than my ultra primitive high school hybrid analog-digital language translator--but it worked. Briefly, a word was dialed letter-by-letter into a panel of si...
by Forrest Mims III
Thu Jan 15, 2009 3:04 pm
Forum: General Discussion
Topic: The newest registered user is Forrest Mims III
Replies: 26
Views: 6174

To sofaspud. Glad to know your father read my column in the Seguin GAZETTE-ENTERPRISE. That column began a decade ago and continues today. The San Antonio EXPRESS-NEWS began running the column ("The Country Scientist") more than two years ago. To Dean Huster. Great to hear from you. Since 1992 I've ...
by Forrest Mims III
Fri Jan 02, 2009 9:25 am
Forum: General Discussion
Topic: The newest registered user is Forrest Mims III
Replies: 26
Views: 6174

Bob, Just noted your post about hand-lettered/drawn circuits. My first hand-lettered books (Engineer's Notebook, vols 1 and 2) were India ink on Mylar. This was not easy and even caused my middle finger to bleed. Worse, errors were impossible to correct. So I switched to a 0.7mm mechanical pencil (w...
by Forrest Mims III
Thu Jan 01, 2009 9:36 am
Forum: General Discussion
Topic: Using Miniature Thyratrons to Drive High-Power Diode Lasers
Replies: 0
Views: 978

Using Miniature Thyratrons to Drive High-Power Diode Lasers

Kevin, Yes, you can think of a MOSFET switching transistor as a kind of solid state thyratron. I once used miniature thyratrons made by EG&G to apply 100 amp pulses to GaAs laser diodes. The pulses were very brief (20-50 nsec) and had ultra-fast risetimes. The power supply was two 67.5 volt batterie...
by Forrest Mims III
Thu Jan 01, 2009 9:16 am
Forum: General Discussion
Topic: Solar tracking without an optical tracker
Replies: 23
Views: 4446

MrAl, You asked if the microcontroller method might be overkill. Seems to me that simpler is better, but arguments can be made that either optical tracking or a microcontroller is simpler. Perhaps I'm biased: 1. When taking various sunlight instruments to remote locations, I have to initiate them wi...
by Forrest Mims III
Mon Dec 29, 2008 7:54 am
Forum: General Discussion
Topic: LED light experimentation
Replies: 22
Views: 6757

mklepper, the action spectrum for DNA damage leading to cancer peaks well below the 360-380 nm range of UV-A LEDs. In outdoor sunlight, the peak is about 305 nm. See Setlow's classic paper "The Wavelengths in Sunlight Effective in Producing Skin Cancer: A Theoretical Analysis" (abstract is at http:/...
by Forrest Mims III
Sun Dec 28, 2008 8:28 pm
Forum: General Discussion
Topic: Workbench Design Challenge Winners!
Replies: 5
Views: 10366

Vern's Workbench

As I noted in an aside to Vern, the surface of his workbench is identical to the workbench I used back in the early 1970s. A photo of it is at http://www.sunandsky.org/MITS_History.php I still use a plywood workbench--but the one in the photo linked above has been retired for sentimental reasons. Fo...
by Forrest Mims III
Sun Dec 28, 2008 7:18 pm
Forum: General Discussion
Topic: Workbench Design Challenge Winners!
Replies: 5
Views: 10366

Congratulations and Thanks

Congratulations to the winners and thanks to Vern for a great idea.

This is probably the most concise set of electronics workbench ideas ever assembled.

Forrest M. Mims III
www.forrestmims.org
www.twitter.com/fmims
by Forrest Mims III
Sun Dec 28, 2008 7:08 pm
Forum: General Discussion
Topic: LED light experimentation
Replies: 22
Views: 6757

Blue Light Source

Seems to me that an optical fiber (as suggested above) is a viable solution. Consider that: 1. You can abrade the end of a plastic fiber to cause light to be scattered out the sides of the fiber over any length you chose. Ordinary sand paper or a small file will work. 2. A fiber will allow you to va...
by Forrest Mims III
Sun Dec 28, 2008 6:58 pm
Forum: General Discussion
Topic: Fence Story
Replies: 17
Views: 4751

Electric Fence Zaps Lizard

Several weeks ago I was down by the creek on our place when I heard a loud popping sound. I walked toward the source and spotted a neighbor's electric fence. Soon I found the source of the popping, for a anoloe lizard was suspended between a barbed wire fence line and the electric one. Each second a...
by Forrest Mims III
Sun Dec 28, 2008 6:51 pm
Forum: General Discussion
Topic: Solar tracking without an optical tracker
Replies: 23
Views: 4446

Solar Tracking

There are various ways to calculate the position of the sun based on your coordinates, date and time of day. Long ago I developed a set of algorithms to do this for calculating the angle of the sun for a long seriers (since 1990) of daily sun measurements. But there's much to be said for optical tra...
by Forrest Mims III
Thu Dec 18, 2008 6:09 pm
Forum: General Discussion
Topic: The newest registered user is Forrest Mims III
Replies: 26
Views: 6174

Checking in with like minded experimenters

Greetings Electronics Experimenters, Thanks very much for the kind greetings. I've read Nuts and Volts for years and should have joined the forum long ago. While I still do circuit design, most of my time is spent using instruments, which I either designed and built or professional versions of the s...