![]() ![]() Switching supplies started to gain popularity at the end of the 70s, as they had several advantages over linear supplies. And as these were made of iron and copper, they weighed a lot. To make a linear supply with a high current output, like a box full of first-generation microprocessor and TTL chips needed, you had to use a physically large transformer. Most of that size, and almost all their tremendous weight, was because they employed linear power supplies. If you recall the very first personal computers, such as the Altair, IMSAI, or Southwest Technical Products boxes, you may remember that they were huge. Linear supplies were the “king of the hill” until the late 1970s, so they were used on a number of earlier computers. We will be working with some of these soon Switching Power Supplies But for most applications, we can take advantage of voltage regulator integrated circuits, many of which only have three connections. Its purpose is to provide a fixed voltage that stays the same under different loads and different AC input voltages.Įarly voltage regulators used discrete parts, and many high-performance designs still do. Voltage RegulatorsĪ voltage regulator is an additional electronic circuit that is connected to the output of an unregulated power supply. Its output voltage will vary based upon the load drawn, and it will also be affected by fluctuations in the input AC line voltage. To be precise, it is an unregulated linear power supply. The system I just described is a linear power supply. The DC produced was noisy and fluctuated at the same rate as the AC line frequency, so a large capacitor was used to smooth it out.Īnd you now have DC power, created from AC! This low-voltage AC was then sent to a rectifier, a device that creates DC from AC. High voltage AC was passed through a transformer, which reduced it to a much lower voltage. Once upon a time, about 50 years ago, most DC power supplies worked the same way. Let’s begin by looking at the two different types of DC power supplies, Linear and Switching supplies. Both of those designs used premade switching supplies. A few years ago we converted an old computer ATX power supply into a useful bench supply, and we also built a simple variable DC power supply as well. Knowing how they work and how to use them is a fundamental electronic skill, one that you can apply to solve a number of design problems.Īnd we have already built a few power supplies here in the DroneBot Workshop. Power supplies are used for equipment like televisions, audio receivers, computers, and about a million other devices. Instead, we use a DC power supply, a device that takes AC current (mains or line current, depending upon where in the world you are) and converts it into safe low-voltage DC at the desired voltage level.Īn excellent example of this is the USB “wall wart”, those ugly little boxes that hang onto wall outlets and provide 5-volt power via a USB cable (newer USBC supplies can provide other voltages as well). While batteries could be used to supply these low voltages, they have several disadvantages, including cost and incorrect voltages. There are, of course, many means of obtaining that power, ranging from batteries to generators to solar cells.įor our experiments with microcontrollers and electronics, we usually require a source of Direct Current, or DC power, quite often at a specific voltage such as 3.3 or 5 volts. IntroductionĮvery electrical or electronic device needs a source of power. We will then put our knowledge to work and construct a linear power supply that would be an excellent addition to your workbench. We’ll learn how they work and which applications they are best suited for. ![]() Today we will be working with Linear Power Supplies. 2.1 Comparing Linear and Switching Power Supplies. ![]()
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |