Power: While cable manufacturers always list the maximum charging rate, your device will determine how much power to draw, so it's important to know what standards it supports and combine your cable with the correct power adapter. The charging rate of a cable is measured in watts (W). Sometimes manufacturers will list specifications on the cable in tiny print. If there’s no W listed, you can calculate it by multiplying the voltage (V) and the current (A), assuming they are listed.

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A long charging cable lets you place your devices wherever you want while charging (or continue using them without crouching at the outlet). This braided nylon cable from Anker is a durable option with a lifetime warranty. It is 10 feet long and can go up to 100 watts, which is enough to fast-charge practically any laptop, phone, or tablet, and it comes with a handy cable tie. You can get it in black or white, but I like the red, as it is easy to spot and less of a tripping hazard.

Cables are usually included in the box for whatever device you purchase. These are generally capable of charging the device at the maximum rate. Keep it safe, keep it simple, and if it is unmarked, consider labeling it.

★ Alternative pick: I use the Smartish Cable Wrangler ($30) on my desktop to stop cable ends from disappearing off the back of my desk. It works great with metal connectors, but for some cables, you must attach a special cable collar that sticks magnetically (you get three in the box).

In the previous example we considered a sensor with 4 micron pixels used with an objective with 40X magnification and a numerical aperture of 0.8. The sensor and magnification provide 100 nm geometric resolution. However, due to diffraction, the sample image resolution will be greater than 100 nm. For example, yellow green light has a wavelength lambda of 550 nm. Using the above equation, the diffraction limited resolution is actually 419 nm. Therefore, the resolution of the sample is > 4 times the geometric resolution at the camera sensor which results in oversampling. While some oversampling is appropriate, 4 times is excessive and a waste of sensor pixels. Calculate the diffraction using our calculator.

Some devices with USB-C ports (certain camera accessories, portable battery packs, and other cheap gadgets) can only charge using a USB-A to USB-C cable instead of a USB-C to USB-C. Usually, this is because USB-C charging ports use the Power Delivery protocol and need to be told the required voltage by the device charging, which means it needs a controller chip. This USB-IF certified, braided nylon cable should do the trick and offers reasonably speedy charging and data transfer to boot.

The consequence of numerical aperture is that it directly relates to the Depth Of Field (DOF). For a given objective, looking at a sample, there’s a particular plane of perfect focus. The depth of field is, how far above and below that plane the objective and sample can be and still have everything in focus.

where Sensor Diagonal is the diagonal size of the camera sensor in millimeters (similar to specifying a TV size), and Objective Magnification is the magnification of the objective lens being used.

Resolutionof microscope formula

Keeping cables neat and orderly, ready to grab and plug in when you need them, requires a little help. I’ve tested various cable management options, and these simple clips from Syncwire are my favorites. You get five stick-on strips in the pack with between one and five slots for holding cable ends neatly in place. They stay put, hold your cables securely, and are fairly unobtrusive.

Don't worry. We dived into the dreaded box of cables, identified the ones you need for various scenarios, and untangled them, ready for use. You'll find some advice here on USB-C, Lightning, and MicroUSB connectors, as well as a primer on everything you need to know about cables. After all, we're WIRED.

In this video, we will explain key optical imaging formulas and how they help in designing your automated digital microscopy imaging applications. Download Microscopy Calculator

If you're looking for a USB-C to USB-C cable that can handle fast charging and speedy data transfers, look no further than this Anker cable (USB 4 Gen 2). It is rated to carry 240 watts, meaning it can power the beefiest MacBook Pro and transmits data at up to 20 gigabits per second (Gbps). It's USB-IF certified, which means it has been tested to ensure it complies with standards set by the USB Implementers Forum. Anker describes it as bio-based because around 40 percent of the exterior is made from corn and sugarcane. The downside? It's only 3 feet long.

This cable matches our top pick on most features, with 40 Gbps data transfer and support for displays up to 8K at 60 Hz, but it also includes Extended Power Range support to charge Power Delivery devices at up to 240 watts. Some laptops top out at 100 watts anyway, so check before you buy, but for those that can handle the extra power this cable will be the speediest option. It’s also braided and tangle-resistant.

Data: The data transfer speed is always in megabits per second (Mbps) or gigabits per second (Gbps). You'll know the speed a cable should be capable of by the standard:

USB Standards: The Universal Serial Bus (USB) standard dates to 1996 but has seen many new standards, revisions, and connector types in the years since. Instead of running through all of them here, we try to highlight what matters.

Updated November 2024: We added cables from Anker, Scosche, UGreen, and Native Union, added specs tables for each entry, removed several older picks, and updated prices throughout.

Numerical aperture and resolutioncalculator

Besides the magnification, reducing the size of the sensor down to the size of the field of view on the sample also does the same with the pixels. For example, a sensor with 4 micron pixels and a 40X objective would be 0.1 micron of geometric resolution or 100 nanometers. But it turns out it isn’t quite that simple. There’s a property of light that acts like a particle, the photon. It also has a wave property. The wave nature of light leads to a condition called diffraction, and due to diffraction, limits are set on resolution. To better understand how that works, we need to explore another concept, which is called numerical aperture.

The two shorter-length cables are passive, and the 6.6-foot cable is active. (Active cables have an extra chip inside to help them push data further without degradation.) I’ve been testing the two shorter cables and have yet to find anything they can’t do. The cables come with a one-year limited warranty in the US (lifetime limited warranty in the UK and a two-year limited warranty in the EU).

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Resolutionof light microscope

You will never find yourself without a cable again if you slip this clever, compact, Swiss-designed multi-cable onto your key ring. It offers six charging combinations, with USB-C and USB-A on one end of the short braided cable, and Lightning, MicroUSB, and USB-C on the other. It can charge most devices at full speed and can be used for data transfer in a pinch. The USB-C connectors felt a little tight in some devices and the unusual Lightning and MicroUSB combination confused me at first, but it works. This improved version adds a cap to protect the connectors, but you must be careful not to misplace it. If you need a longer multi-cable, the InCharge XL ($29 to $39) is available in 1-, 6.6-, and 10-foot lengths.

With various standards and charging technologies at work, it is much harder than it should be to work out what a cable can do. There are a few things worth knowing when shopping.

To better understand diffraction imagine if light moved strictly in straight lines. If a pinhole is illuminated with some light, the light would be directed in a straight beam. What actually happens is due to the wave nature of light, the light is diffracted, and instead of going straight, it spreads out into a cone. As shown in the diffraction image, the brightest light is the zero-order straight through, then the intensity decreases for the first order, second order, third order, etc. Unless the objective is capturing all of those higher orders, it is difficult to synthesize a high-resolution image. This describes what the fine structure of your sample is doing, it could be cells, chromosomes, or nuclei, and all of that fine structure spreads the light out.

If you are curious about the charging rate of a device, this USB-C to USB-C cable from Baseus can tell you. It sports a tiny blue LED display that's built into one of the ends, and when you plug it in, the charging rate pops up in watts. When I measured it against my digital USB tester, it appeared accurate, though it rounds up to the nearest whole watt. It maxes out at 100 watts, so it can fast-charge most gadgets but is not a good pick for data transfer. The braided nylon finish and metal ends feel durable.

When designing automated digital microscopy devices for life science, biomedical, and diagnostic applications, typically, our goal is to optimize the device for the highest resolution image and the highest throughput in images per second. Microscope calculations such as magnification, resolution, microscope field of view, depth of field, and numerical aperture help us determine various aspects of a microscope’s capabilities and simplify the modeling and prototyping process. In this article, we will cover the importance of microscope calculations in optimizing microscope performance for your specific application.

The microscope field of view stands for the area of the sample visible through the microscope, which is calculated by dividing the sensor diagonal size by the magnification of the objective lens. For instance, a 20 mm diagonal sensor with a 20X objective lens would yield a Field Of View (FOV) of 1 mm, typical for microscopy applications. Microscope field of view can be calculated using the following formula:

Cable Certification: There are a few types of cable certification. When a cable is certified, that usually means it was independently tested and conforms to specific standards. It gives you, as a buyer, peace of mind that your cable performs as the manufacturer claims. Certification can be expensive, so many cable manufacturers shun it, but that doesn’t necessarily mean their cables are poor quality. The USB Implementers Forum (USB-IF) is a non-profit organization dedicated to advancing USB technology. Run by members like Apple, Google, HP, Microsoft, and Intel, it sets specifications and offers certification. If a cable is certified by the USB-IF, it has been tested to ensure it complies with its standards. Apple has its own Made for iPhone (MFi) certification for Lightning cables. Intel certifies Thunderbolt cables. Certified cables usually have the relevant logo on the connector. (For example, Thunderbolt cables have a lightning bolt.)

Most USB-C cables are dull and easy to lose in the tangle of your bag or, worse, your box of cables. This fun cable from Sharge looks like what Chewy might pass you if you asked for a power coupling. Impossible to lose, this yellow cable has molded plastic ends in what Sharge calls a “cyberpunk style.” Although they look suitably sci-fi they are also quite big, which could be an issue if space is tight at the USB-C port you are using. When you plug something in to charge, both ends of the cable light up. It can charge phones, laptops, and maybe even droids, as it carries up to 240 watts, but it’s quite slow for data transfer. It also comes in purple or gray.

The image below shows a variety of microscope systems. There are multiple magnification objectives depicted: low power 4x, medium power, 40x and high power 100x. The distance from the end of the objective to the sample, which is called the working distance, is going to be larger on a low power objective, less on a medium power and very fine, possibly a fraction of a millimeter for the high power system. What’s critical is the angle. The sample is illuminated and light is coming out of it. In the case of the shorter working distance, higher numerical aperture objectives, that light is coming at an increasingly higher angle. The Numerical Aperture (NA) of the objective equals the sine of the half-angle (theta divided by two where theta is the entire angle). Read more on how to calculate the numerical aperture.

Numerical apertureof 100X objective lens

There is something to be said for the simplicity of getting the most capable USB-C cable you possibly can, and right now, an Intel-certified Thunderbolt 4 cable like this one will meet all your needs. It carries 100 watts, enough to charge a laptop, and it can transfer data at up to 40 Gbps. It’s capable of serving an 8K display (or two 4K displays). It supports both DisplayPort Alt Mode (DP Alt Mode) and USB Power Delivery (USB-PD), including PPS, which enables fast charging for certain Samsung devices, and it is backward-compatible with all earlier standards.

When it comes to digital imaging sensors, there is a wide variety to choose from. The main camera sensors used are CCD (charge-coupled device) or CMOS, Complementary Metal Oxide Semiconductor. For cutting edge performance, to reduce read noise, large and expensive cameras exist with liquid or Peltier coolers (deep cooled to about -60 degrees Celsius). Also, EMCCD (Electron Multiplied CCD) cameras allow for single photon detection and are popular for live cell imaging applications. Learn more about key aspects of image sensors common to both CCD and CMOS devices, starting at the pixel level in our "CCD Image Sensors" whitepaper.

You can save a few dollars by going with this USB-C to USB-C cable, and you don’t have to sacrifice, because it is capable of 100-watt charging and 10-Gbps data transfer. You can even use this cable to connect a laptop to a 4K display. So, what’s the catch? Well, it is very short, finished in plain black plastic, quite thick with relatively long connectors, and not very flexible. But these specs at this price make it a total bargain. It is USB-IF certified and comes with a lifetime warranty.

A larger field of view is generally desirable, as it allows for a larger area of the sample to be viewed at once, making it easier to locate and navigate to specific areas of interest. However, as the magnification increases, the field of view decreases, making it more difficult to observe larger areas of the specimen at higher magnifications. Need help with microscope calculations? Download our calculator.

Numerical aperture and resolutionin microscope

To summarize, for high imaging resolution a high numerical aperture objective is required and one of the consequences of that is a fairly small depth of field which places an emphasis on the quality and performance of your focusing stage and XY sample positioning stage. Dover Motion has developed the DOF-5 specifically for microscope objective focusing.

Perhaps you just want a cable that will charge all of your gadgets at the maximum possible speed and you don’t care about data transfer. If so, the Anker Prime is the USB-C cable for you. The braided nylon exterior is tough and made from 100 percent recycled plastic. Anker promises this cable will last a century and it can operate in temperatures from -40 degrees to 176 degrees Fahrenheit. I love the ribbed cuffs, because they make it easier to grip for plugging and unplugging. It is USB-IF certified and comes with a lifetime warranty.

Numerical apertureof microscope

Microscope calculations are specific to the imaging sensor and microscope objective selection, which also impacts the performance requirements of the sample XY motion and Z focusing motion.

If you want to avoid contributing any more plastic to the world, these cables might tempt you. They boast an eco-friendly build with a flexible knit fabric finish crafted from certified recycled plastic and aluminum that looks (and feels) lovely and promises to last. WIRED reviews editor Julian Chokkattu has been using a few of these for years with zero issues. Available in three lengths with a two-year warranty, they charge at a rate that should be good enough for most portable devices, but they're slow for data transfer.

The sample is throwing light out in all directions and the job of the objective is to collect as much of that light as possible. The way to do that is to have a high numerical aperture, a big wide cone. If the objective doesn’t collect a wide-angle of the cone, for example, a long working distance, low power objective will merely be getting the light that’s going straight through. That is why numerical aperture is the key to high-resolution imaging. There is one other variable that can be adjusted. By using bluer light, the resolution can be increased, but for a particular application, that may not be possible. Generally speaking, for any given objective, it is worth it to pay to get the highest possible numerical aperture, but there is a slight downside to that.

Connectors: While USB-C is mercifully becoming a standard connection type, you want cables with connectors that fit your existing devices. Today, that still might mean USB-A, Lightning, or even MicroUSB. Remember that the capabilities of any cable are limited to its oldest connection type.

Covers key formulas for selecting the optimal imaging sensor and microscope objective for your digital imaging application including sensor size, magnification, field of view, pixel sizes, resolution, depth of field, and numerical aperture.

Basic USB-C cables are passive and can only carry up to 60 watts. Cables that can carry 100 watts or more, sometimes described as active, must contain e-marker chips that identify the cable and its capabilities.

Check your device's standards. Look for a cable that matches your needs. For example, if your device supports Power Delivery, then get a PD cable. Remember: The charging adapter also must support the same standards. We have more details about standards at the bottom of this guide.

Numerical aperture and resolutionformula

Thunderbolt was a proprietary interface developed by Intel and Apple, but it's now open for royalty-free use (still certified by Intel). With Thunderbolt 3, the standard adopted the USB-C connector and is capable of data transfer speeds up to 40 Gbps and can deliver 100 watts of power using the PD standard. Thunderbolt 4 brings various improvements mostly related to the video signal (support for two 4K displays or an 8K display). It also supports the USB 4 standard and is backward compatible with previous standards.

Avoid tangles with this clever retractable cable from Baseus. Available in a few fun colors, this flat cable comes rolled up inside a circular case. Pull the USB-C ends and you can fix it at preset lengths (1.1, 1.9, 2.7, or 3.3 feet). When you’re done, simply pull and release it to have the cable coil back up inside the case.

For a low power 4x system, the numerical aperture is going to be very low, on the order of 0.05 to 0.1. In a medium power 40x system, it could be in the range of 0.5 to 0.8 and for a high power system, it can be as high as 0.9 or 0.95. As long as there is air between the objective and the sample, the numerical aperture can never exceed 1. When imaging slides, in order to exceed an NA of 1, a liquid can be added between the coverslip and the objective. Typically, oil or water are used for this and the objectives are referred to as oil immersion or water immersion objectives. With water, the numerical aperture goes up to about 1.1 and using oil, the numerical aperture can go up to as high as 1.47.

For 20X magnification, which can be a numerical aperture of 0.6 to 0.8, the depth of field drops to about plus or minus 500 nanometers. Moving into high magnification with oil immersion at a numerical aperture of 1.47, the depth of field drops very dramatically, And the depth of field could be plus or minus 0.1 to 0.2 microns (100 – 200 nm). That’s a very tight tolerance. At 100 nanometers or 200 nanometers, very tiny changes in flatness of the sample or the height of the sample, or the precision of the guideways of the XY sample motion stage, will make it tricky to stay in focus. For maintaining focus in this situation, a continuous tracking laser auto-focus system connected to a high bandwidth objective focusing stage, such as the DOF-5, is the ideal way to maintain focus in these high numerical aperture, high-resolution applications.

There are so many cables out there, and plenty of solid options did not make the cut. Here are a few I’ve tested and liked.

Numerical apertureof microscope formula

To optimize the field of view for a particular application, it is vital to consider the size of the specimen and the level of detail required. For example, if a large sample with low detail is being observed, a lower magnification and larger field of view may be more appropriate. Conversely, if a smaller specimen with high detail is being observed, a higher magnification and smaller field of view may be necessary to achieve the desired level of resolution.

The Power Delivery (PD) standard is as close as we have to a common standard. A few manufacturers, like OnePlus, Oppo, and Xiaomi, still have proprietary charging standards. Then there's Qualcomm’s Quick Charge (QC) standard, which was the most popular for phones for many years, although Quick Charge 4+ supports PD. Even PD has a variant called Programmable Power Supply (PPS), which is part of the USB PD 3.0 standard. PPS allows for real-time adjustments to maximize efficiency and charge phones like Samsung's Galaxy S22 range at up to 45 watts instead of the usual 18. The latest addition to PD is Extended Power Range (EPR), which allows USB-C cables to carry up to 240 watts (they used to be limited to 100 watts).

The humble cable is often the simplest and fastest way to charge your devices or move files from one device to another. But these ostensibly straightforward power and data conduits come in many shapes and sizes. Even cables that appear identical may perform differently when you plug them into your phone or laptop. Various connectors, specifications, charging rates, and data transfer speeds make for a confusing, messy scene.

Poorly made cables can overheat and start fires. To boost your chances of buying a dependable cable, look for USB-IF certification or stick to trustworthy brands like Anker, Cable Matters, or Syncwire.

In most cases the material between the objective and sample is air, and “n” equals 1.00. For water, it’s refractive index is 1.33, and specialized immersion oil for microscopy is 1.52. For a low magnification objective such as a 4X or even a 10X, the typical depth of field is plus or minus 3 to 5 microns. In that case, if the sample is very flat, focusing may not be required at all, or only one needs to happen one time. Generally speaking, samples vary in thickness and they vary in flatness, so focusing is required.

Apple's cables are notoriously bad. The casing around the wires easily falls apart over a short period of time, so it's smart to invest in a durable USB-C to Lightning cable. This thick braided cable feels tough and is Made for iPhone-certified (MFi), so will work perfectly with your iPhone or iPad. There are USB-C to Lightning and USB-C to USB-C versions.

This is called the depth of field. The formula for the depth of field is: where: “n” is the refractive index of the material between the objective and the sample λ (lambda) is the wavelength of light NA is the Numerical Aperture

If you’re looking for a way to plug your USB-C device into a monitor or TV, this adapter can help. The USB-C to HDMI cables and adapters scene is a minefield for compatibility, so do your research first to ensure you get something that works. Provided your desktop, laptop, tablet, or phone supports DP (DisplayPort) Alt Mode, you can use this adapter to switch to HDMI 2.1 (you will still need an HDMI cable). It’s a durable aluminum adapter with a braided cable, and it supports 8K at 30Hz or 4K at 120Hz. It can also handle 4K at 144Hz if the USB-C source is DP 1.4 and the monitor is HDMI 2.1, but it is limited to 4K at 60Hz for Macs. The adapter supports HDR and is lag-free, making it a solid choice for hooking up to the latest gaming monitors, though sadly, it does not support VRR, FreeSync, or G-Sync. We recommend you check compatibility before you buy.

Folks looking to add connectivity to a laptop using the USB-C port should consider this compact and versatile hub from Anker. It is an affordable option in our Best USB Hubs and Docks guide that plugs in via the attached USB-C cable to give you two USB-A 3.0 ports, an HDMI output, and a full-size and MicroSD card reader. Using HDMI, you can get 4K video output at 30 Hz or 1080p at 60 Hz.

You can use USB-C for displays. Manufacturers will state the data transfer speed or list support for 4K or 8K video on select cables. That means you can just use a USB-C to USB-C cable to transmit video from your laptop to your monitor. You should consider DisplayPort Alt Mode (DP Alt Mode) support, as this enables you to hook up displays and video sources that support DisplayPort.

Some pets like to chew charging cables, and some people just seem to wear through cables faster than others. If you've been looking for a more durable option, this Fuse Chicken cable should do the trick. The cable combines aluminum sleeves with several layers of cable protection, including Kevlar and stainless steel chainmail. They are not as flexible as other cables and are relatively heavy and pricey. But Fuse Chicken does offer a lifetime warranty. I encouraged my cat to attack one of these cables (when it wasn't plugged in!), but it still works and is unscathed.

It is safe to use your phone while it is charging, but it will charge at a slower rate. Heat is also bad for battery health, so it is best to take a break when your phone feels warm.

The same thing occurs in traditional photography, a very small aperture will increase the depth of field. A higher numerical aperture will give a higher resolution, but the depth of field becomes considerably smaller. There is a distance above the sample plane and a distance below the sample plane, and anywhere within them, there is essentially perfect focus. As soon as the objective and sample are outside of that boundary, the image begins to blur.

When you have multiple devices with varied charging ports, you often need multiple charging cables, but this clever offering from Smartish packs three connection types into one. It is technically USB-A to MicroUSB, but there's an adapter at the tip that converts it to USB-C or Lightning. It has a durable fabric finish in a choice of four colors and can charge most of your gadgets at top speed. WIRED review editor Julian Chokkattu has used it to juice up a range of devices, from wireless keyboards to a Fire tablet. It's also MFi certified for Apple devices.

In addition to affecting the observation of the specimen itself, the field of view can also impact the ability to capture high-quality images and videos. A larger field of view requires a larger camera sensor or eyepiece, which can increase the cost of the microscope system. It is essential to consider the balance between field of view, magnification, and cost when selecting and optimizing a microscope for a particular application.