As already mentioned, most electric grinders have parallel grinding wheels. An example of such devices is Vityaz TE-150.
This sharpener is versatile and intended for use at home. The frame Vityaz TE-150 is attached to the work table with the help of special suction cups. Each sharpener disc is covered with a plastic protection. The mass of the device in question is 6.3 kg.
On some sharpeners, the abrasive wheels are set perpendicular to each other. An example of such a product is Energomash TS-6022U.
This sharpener is intended not only for sharpening various tools, but also for dry and wet grinding. During wet grinding, the abrasive wheel is in a tray with water and rotates at reduced speed. Electric grinder Energomash TS-6022U has a cable for connecting to the mains 1.5 meters long, so you can place it in any convenient place.
If you are interested in the possibility of sharpening drills, then power tool manufacturers produce special sharpeners for this. The Temp MZS-100 is just such a device.
As we can see from the figure, drill sharpeners are significantly different from conventional electric sharpeners and therefore they are specialized power tools, and not universal.
Along with electric sharpeners, there are also conventional sharpeners designed for sharpening various cutting tools. Moreover, such sharpeners can be of various sizes. Some sharpeners, such as the Lansky 6 x 2 Diamond Bench Stone XC (1568.06.27), are large and lightweight, making them very convenient for home use. But, naturally, such a winepress cannot be taken with you on a hike or to the sea. For such purposes, there are folding portable sharpeners. An example of such a product is the Lansky Folding Diamond Paddle CR / FN (1568.06.20). Outwardly, such a sharpener looks according to the following figure.
The Lansky Folding Diamond Paddle CR / FN (1568.06.20) has dimensions of only 8.9 x 1.9 cm, so it does not take up much space in your luggage and can help you out at any time when you are outdoors. After all, any knife can become dull very quickly and become unsuitable for cutting food.
Conclusion
When choosing a sharpener, you should first decide for what purposes you need it. Indeed, at present there are a huge number of different sharpeners, each of which has both advantages and disadvantages.