7,710 reputation
11330
bio website embedinc.com/olin
location Littleton, Massachusetts
age 58
visits member for 2 years, 2 months
seen 5 hours ago

Electrical engineering consultant specializing in microcontrollers and the circuitry around them. Master of engineering in EE from Rensselaer Polytechnic Institute in 1980.

We are certified Microchip design partners, and have been in the top catagory consistantly since around 2000. Various free downloads related to developing PIC firmware and other things are available at http://www.embedinc.com/pic/dload.htm.


Feb
3
comment Is there something equivalent to a diode for light?
No, a ideal diode doesn't consume any power. It is simply a one-way valve for current, which doesn't require any external power to operate. Some specific implementations do take external power, but that's a engineering issue.
Jan
30
comment Wavelength of X-rays in a tube
Actually, the wavelength of xrays produced is a function of the energy electrons have when hitting the anode. Perhaps you are seeing secondary re-emissions?
Dec
25
comment Why is concrete dry around cracks?
@Foris: That's a good idea. There is not water outlet anywhere near there, but I'll see what I can come up with next summer.
Dec
25
comment Why is concrete dry around cracks?
@Floris: It's winter here now. I think this is a summer phenomenon, so it'll be some months before I can collect more data. Short rain squalls with heavy drops are not that unusual, but they come without warning, and for best results it seems I need to photograph it within 2-3 minutes. I'll try to be vigillant next summer, but it's not certain I'll catch anything good.
Dec
24
comment Why is concrete dry around cracks?
@Brandon: But the effect can be seen some distance from the crack, a few inches in some cases. Also note that the entire effect happend in about 3 minutes, maybe 5 by the time the picture was taken.
Dec
24
revised Why is concrete dry around cracks?
added 185 characters in body
Dec
24
comment Why is concrete dry around cracks?
No, this is definitely not it. See my point #3 in the question. There was never enough water on the ground at any time to flow. Also, selective dryness due to water flowing into cracks looks quite different. The dryness is only on the downhill side of each crack. Note the dry areas in the picture surround the crack on both sides about equally and regardless of crack orientation relative to slope.
Dec
24
asked Why is concrete dry around cracks?
Dec
24
revised Does water maintain equal level in connected vessels?
added 943 characters in body
Dec
24
answered Does water maintain equal level in connected vessels?
Dec
23
answered Do infrared lamps provide more heat than incandescent lamps?
Dec
5
awarded  Famous Question
Nov
29
answered Impulse and force in a karate chop, can we maximize force minimizing the time of impact?
Nov
19
comment Car driving / falling off of a cliff - will it land upright?
I don't think it really matters much where the center of gravity is relative to the two axles. No matter where it is, you get the same net torqe impulse from the back wheels being pushed up while the front wheels have already gone over the edge. This is where the rotation comes from. Center of mass relative to shape will eventually dictate what happens due to air resistance, but I'd say that is minimal in a 1/2 to 1 revolution fall for a typical car or van.
Nov
19
comment Car driving / falling off of a cliff - will it land upright?
The speed effects the net torque impulse imparted during the time the front wheels are over the edge but the back wheels not yet. This effects the rotation speed, which in turn effects the fall distance for one complete revolution.
Nov
19
answered Car driving / falling off of a cliff - will it land upright?
Oct
31
answered The sound of rotating helicopter blades
Oct
30
comment Can you pre-determine the result of a coin toss?
You left out air resistance, which I suspect has some impact on the outcome.
Oct
29
comment Silicon/silicon dioxide interface
You seem to be confusing a semiconductor junction with bulk semiconductor material. Photocells work like what you describe, but only when the photon hits in a semiconductor junction. The principle doesn't work in bulk semiconductor material, whether doped or not.
Oct
29
comment Bungee jumping - find spring constant
@Floris: I don't know, as that would require actually reading your answer. I saw a bunch of equations and "harmonic oscillator" mentioned in your first sentence, so thought I'd give a simpler answer.