With the advent of newer technologies, lighthouses and their Fresnel lenses have lost their usefulness, and many have disappeared or have been destroyed as ...

What a bizarre, defeatist PR position. They might as well spill the whole story of how it came to be then. Selling trinkets for a few bucks is hard to survive in Van Nuys….

It is the end of an era. I remember ordering stuff from them way back. I enjoyed their catalogs and browsing their website. They kind of remind me of American Science & Surplus ( sciplus.com ) and Surpluss Shed ( surplusshed.com ) for optics. With those surplus stores you never knew what random item you might come across. Hopefully the latter ones stick around a little longer.

Tayda Electronics

Before the advent of the CCD beam profiler, the beam width was estimated using the knife-edge technique: slice a laser beam with a razor and measure the power of the clipped beam as a function of the razor position. The measured curve is the integral of the marginal distribution, and starts at the total beam power and decreases monotonically to zero power. The width of the beam is defined as the distance between the points of the measured curve that are 10% and 90% (or 20% and 80%) of the maximum value. If the baseline value is small or subtracted out, the knife-edge beam width always corresponds to 60%, in the case of 20/80, or 80%, in the case of 10/90, of the total beam power no matter what the beam profile. On the other hand, the D4σ, 1/e2, and FWHM widths encompass fractions of power that are beam-shape dependent. Therefore, the 10/90 or 20/80 knife-edge width is a useful metric when the user wishes to be sure that the width encompasses a fixed fraction of total beam power. Most CCD beam profiler's software can compute the knife-edge width numerically.

We had a great run and much if not nearly the vast majority sadly of remaining manufacturers of these products aren’t made domestically anymore and haven’t been in decades in many cases. Sure there is a need for skilled labor and I’ve been saying that since the 70’s yet automation and innovation have made this a relic of the past.

The beam diameter or beam width of an electromagnetic beam is the diameter along any specified line that is perpendicular to the beam axis and intersects it. Since beams typically do not have sharp edges, the diameter can be defined in many different ways. Five definitions of the beam width are in common use: D4σ, 10/90 or 20/80 knife-edge, 1/e2, FWHM, and D86. The beam width can be measured in units of length at a particular plane perpendicular to the beam axis, but it can also refer to the angular width, which is the angle subtended by the beam at the source. The angular width is also called the beam divergence.

Using this general definition, also the beam azimuthal angle ϕ {\displaystyle \phi } can be expressed. It is the angle between the beam directions of minimal and maximal elongations, known as principal axes, and the laboratory system, being the x {\displaystyle x} and y {\displaystyle y} axes of the detector and given by

Electronicparts Surplus Ltd

The D4σ width of a beam in the horizontal or vertical direction is 4 times σ, where σ is the standard deviation of the horizontal or vertical marginal distribution respectively. Mathematically, the D4σ beam width in the x dimension for the beam profile I ( x , y ) {\displaystyle I(x,y)} is expressed as[3]

That said I am old enough to come to terms with the hard reality that this type of business is a relic of the past. This isn’t me being harsh but the blunt reality. Think of the youth of today; with exceptions of course most aren’t interested in the analog or “old school” technology.

I spent much of my youth in the late ’70s and early ’80s hacking together all sorts of electronic gizmos. When I wasn’t skateboarding or doing homework, I was at my desk with a soldering iron and bins of parts from All Electronics and Radio Shack.

The American National Standard Z136.1-2007 for Safe Use of Lasers (p. 6) defines the beam diameter as the distance between diametrically opposed points in that cross-section of a beam where the power per unit area is 1/e (0.368) times that of the peak power per unit area. This is the beam diameter definition that is used for computing the maximum permissible exposure to a laser beam. In addition, the Federal Aviation Administration also uses the 1/e definition for laser safety calculations in FAA Order JO 7400.2, Para. 29-1-5d.[1]

In the early 2000’s shortly after I got into amateur radio I ordered a bit from them as they were one of the easier options available once you wanted more variety than was available from radio-shack. I remember them as having a decent if slightly odd selection of surplus parts and inexpensive new electronics parts. The reasonably sized catalog was a pretty good source back when websites seldom offered online shopping options. Back then Digikey and Mouser Electronics had much smaller offerings and much more difficult catalogs to sift though. I assume that the supply surplus electronics has probably slowed to a trickle as less and less is manufactured here. Along with so many more options for low cost electronic parts (Amazon, Ebay, ECT…) that making a profit in that market would be difficult.

Lee'selectroniccomponents

The main drawback of the knife-edge technique is that the measured value is displayed only on the scanning direction, minimizing the amount of relevant beam information. To overcome this drawback, an innovative technology offered commercially allows multiple directions beam scanning to create an image like beam representation.[4]

All Electronics is an electronics discount store. They carry surplus parts and misc supplies, such as switches, wiring, LED modules, and more.

I didn’t get the email announcing this!! I would have bought a bunch of stuff before they went away forever. For instance, those little rotary 5 position switches (that they apparently had a million of) were on my list to buy on my next order. This stings a bit.

Sad to see them go but the owner must have retired or passed. I’ve been buying electronic parts from them since the 1970’s, away from the big parts stores like Mouser, Newark, Digi-Key, and now Amazon. They and Jameco were my go to.

Jameco Electronics

2024621 — An IR lens is an optical lens designed to collimate, focus, or collect infrared light. At Avantier Inc., we produce high performance IR ...

Beam diameter is usually used to characterize electromagnetic beams in the optical regime, and occasionally in the microwave regime, that is, cases in which the aperture from which the beam emerges is very large with respect to the wavelength.

I got my start in a sort of family business that now has no connection to any of mine. None of the generations that have come after me and my contemporaries had any interest in making their livings in the building trades – so my family – including me slowly – divested ourselves. The difference – perhaps – is that the old businesses, that I was associated with are continuing under a somewhat different set of owners.

As many have commented, I grew up taking for granted places like All – anyone remember PolyPaks ? Or Lafayette Electronics (I’m in NYC). Up until the early 70’s there was a wonder of retail places in downtown Manhattan (“Radio Row”) selling this sort of thing, and WW2 surplus electronics. It was so fun browsing – you never knew what you’d find…often sold by the pound ! I still have some of what I picked up.

I first learned of the company years ago, probably through a magazine ad, and fondly remember going through their slim booklet-style catalogs.

Lots of fond memories skimming through and buying parts from their catalogs…. Especially when I was back in school decades ago, and constantly tinkering with electro-mechanical things. Sad to see them finally go… though I think the writing has been on the wall for a very long time.

This definition also incorporates information about x–y correlation ⟨ x y ⟩ {\displaystyle \langle xy\rangle } , but for circular symmetric beams, both definitions are the same.

For a Gaussian beam, the relationship between the 1/e2 width and the full width at half maximum is 2 w = 2   F W H M ln ⁡ 2 = 1.699 × F W H M {\displaystyle 2w={\frac {{\sqrt {2}}\ \mathrm {FWHM} }{\sqrt {\ln 2}}}=1.699\times \mathrm {FWHM} } , where 2 w {\displaystyle 2w} is the full width of the beam at 1/e2.[2]

Most reading eye glasses give you a maximum magnification of 3X, but these optically correct magnifying glasses are stronger and the focal point is closer, ...

Allelectronics corporation

... Digital Zoom Video Camera with USB Cable (Black). Add. Logitech C505 Webcam 720p HD External USB Camera for Desktop or Laptop Bulk Package Non Retail Box.

Really, I do think the killer is how expensive shipping is, especially in conjunction with the direct-from-China availability of so many things (and the subsidized shipping through USPS making that even more exaggerated).

When a beam is measured with a laser beam profiler, the wings of the beam profile influence the D4σ value more than the center of the profile, since the wings are weighted by the square of its distance, x2, from the center of the beam. If the beam does not fill more than a third of the beam profiler's sensor area, then there will be a significant number of pixels at the edges of the sensor that register a small baseline value (the background value). If the baseline value is large or if it is not subtracted out of the image, then the computed D4σ value will be larger than the actual value because the baseline value near the edges of the sensor are weighted in the D4σ integral by x2. Therefore, baseline subtraction is necessary for accurate D4σ measurements. The baseline is easily measured by recording the average value for each pixel when the sensor is not illuminated. The D4σ width, unlike the FWHM and 1/e2 widths, is meaningful for multimodal marginal distributions — that is, beam profiles with multiple peaks — but requires careful subtraction of the baseline for accurate results. The D4σ is the ISO international standard definition for beam width.

I’m definitely going to miss them. They used have a second loaction in DTLA. I’ve been going there for 20 yrs. I still shop there, I was actually just there 2 days ago & a couple weeks ago. With them gone, now there will be no local surplus stores that sells the type of stuff they had which is sad. There’s Apex but they’re a totally different type of surplus store. A few of the guys there have a plan though & I really hope it works out for them, for their sake & ours.

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As a teen I used to shop these places to build all sorts of projects in magazines like Popular Electronics. That experience encouraged me to get my undergrad degree in electrical engineering. At the university we did build some things in our lab classes, but most of our time was focused on theory. Advance a few decades forward and a person can buy a fairly advanced raspberry pi kit for less than $50 and do everything in software. The market is really shrinking for a lot of these component parts retailers.

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Futurlec

Measurements of the 1/e2 width only depend on three points on the marginal distribution, unlike D4σ and knife-edge widths that depend on the integral of the marginal distribution. 1/e2 width measurements are noisier than D4σ width measurements. For multimodal marginal distributions (a beam profile with multiple peaks), the 1/e2 width usually does not yield a meaningful value and can grossly underestimate the inherent width of the beam. For multimodal distributions, the D4σ width is a better choice. For an ideal single-mode Gaussian beam, the D4σ, D86 and 1/e2 width measurements would give the same value.

You are probably correct. Might have been a family run business. The founder (s) 56 years ago may have passed on or retired. The next generations may not be as keen on the business and think that the building and property (if they own it) is where the real money is.

Old guys i.e. boomers such as me are likely the largest demographic that still are interested in this. From the 1970’s to the mid 90’s there was such a demand and interest with electronics of this nature. However those days are very much long gone and are never returning.

That sux! All the best places to go to build stuff are going away. GEMOLITE, FOAMED PLASTICS, KIT KRAFT, CONTINENTAL GRAPHICS, ALLIED TRAINS, BERGER BEADS, MOSKITELLS, FRYES, among others.

Sad. My dad and I used to peruse their catalogs 30-40 years ago for hard-to-find, discrete components for whatever hobbyist projects we were working on at the time. There were several “mail order” businesses like All Electronics back then; most have probably faded into the sunset.

I do remember some of their electronic connectors being really poor quality. I got a batch of 20 PL-259 connectors that had the softest plastic insulator and only 2 holes to solder the shield instead of the normal 4 holes. Those were a absolute PITA to install without turning the whole thing into a puddle of molten plastic. I did succeed and used all of them up, but learned a good lesson about spending a bit more for better quality.

Beam diameter usually refers to a beam of circular cross section, but not necessarily so. A beam may, for example, have an elliptical cross section, in which case the orientation of the beam diameter must be specified, for example with respect to the major or minor axis of the elliptical cross section. The term "beam width" may be preferred in applications where the beam does not have circular symmetry.

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Mjp electronics

1 The penetration of one substance into or through another, such as the absorption of water into soil, or the uptake of water and nutrients by a cell or ...

My millennial self still orders occasionally from places like this. I’ve known of all electronics for years, but nothing stood out to me about them. I tend to shop goldmine electronics. They tend to have more of the NOS/odd parts I can come up with a use for at reasonable prices.

International standard ISO 11146-1:2005 specifies methods for measuring beam widths (diameters), divergence angles and beam propagation ratios of laser beams (if the beam is stigmatic) and for general astigmatic beams ISO 11146-2 is applicable.[6][7] The D4σ beam width is the ISO standard definition and the measurement of the M2 beam quality parameter requires the measurement of the D4σ widths.[6][7][8]

The angle between the maximum peak of radiated power and the first null (no power radiated in this direction) is called the Rayleigh beamwidth.

Browsing All Electronics is kind of like going through a tinkerer’s spare and harvested parts rack. They’ve got a bunch of useful stuff for prototyping with, but I’d never buy parts or components to spec from there.

IF you can even get a raspberry pi kit. Most places are on backorder through 2024-25. Or on ebay for 4x’s retail pricing.

When I read the headline I momentarily thought a big EMP blast had hit the USA. But then realized my iPhone wouldn’t be working to read the headline if hat was so.

Searched that site for a while and in my opinion, with the high cost of shipping virtually nothing on that website you can get elsewhere for roughly either the same price or maybe somewhat cheaper. Look I am all for supporting small family owned businesses and businesses that aren’t corporations. Heck I even go out of my way if I can to support several I know because they aren’t part of a chain.

Active Surplus, BG Micro and now All Electronics. Who’s next? Jameco? Very sad, but I can see how the market has changed.

The 1/e2 width is equal to the distance between the two points on the marginal distribution that are 1/e2 = 0.135 times the maximum value. In many cases, it makes more sense to take the distance between points where the intensity falls to 1/e2 = 0.135 times the maximum value. If there are more than two points that are 1/e2 times the maximum value, then the two points closest to the maximum are chosen. The 1/e2 width is important in the mathematics of Gaussian beams, in which the intensity profile is described by I ( r ) = I 0 ( w 0 w ) 2 exp ( − 2 r 2 w 2 ) {\displaystyle I(r)=I_{0}\left({\frac {w_{0}}{w}}\right)^{2}\exp \!\left(\!-2{\frac {r^{2}}{w^{2}}}\right)} .

The D86 width is defined as the diameter of the circle that is centered at the centroid of the beam profile and contains 86% of the beam power. The solution for D86 is found by computing the area of increasingly larger circles around the centroid until the area contains 0.86 of the total power. Unlike the previous beam width definitions, the D86 width is not derived from marginal distributions. The percentage of 86, rather than 50, 80, or 90, is chosen because a circular Gaussian beam profile integrated down to 1/e2 of its peak value contains 86% of its total power. The D86 width is often used in applications that are concerned with knowing exactly how much power is in a given area. For example, applications of high-energy laser weapons and lidars require precise knowledge of how much transmitted power actually illuminates the target.

The definition given before holds for stigmatic (circular symmetric) beams only. For astigmatic beams, however, a more rigorous definition of the beam width has to be used:[5]

An Archive of Our Own, a project of the Organization for Transformative Works.

The other definitions provide complementary information to the D4σ. The D4σ and knife-edge widths are sensitive to the baseline value, whereas the 1/e2 and FWHM widths are not. The fraction of total beam power encompassed by the beam width depends on which definition is used.

Electronicgoldmine

The simplest way to define the width of a beam is to choose two diametrically opposite points at which the irradiance is a specified fraction of the beam's peak irradiance, and take the distance between them as a measure of the beam's width. An obvious choice for this fraction is ⁠1/2⁠ (−3 dB), in which case the diameter obtained is the full width of the beam at half its maximum intensity (FWHM). This is also called the half-power beam width (HPBW).

By mechanically moving the knife edge across the beam, the amount of energy impinging the detector area is determined by the obstruction. The profile is then measured from the knife-edge velocity and its relation to the detector's energy reading. Unlike other systems, a unique scanning technique uses several different oriented knife-edges to sweep across the beam. By using tomographic reconstruction, mathematical processes reconstruct the laser beam size in different orientations to an image similar to the one produced by CCD cameras. The main advantage of this scanning method is that it is free from pixel size limitations (as in CCD cameras) and allows beam reconstructions with wavelengths not usable with existing CCD technology. Reconstruction is possible for beams in deep UV to far IR.

Nov 16, 2008 — Magnification. Magnification is the degree to which the object being viewed is enlarged, and is designated on binoculars as the number preceding ...