This November, in Versailles, France, representatives from 57 countries are expected to make history. They will vote to dramatically transform the international system that underpins global science and trade. This single action will finally realize scientists’ 150 year dream of a measurement system based entirely on fundamental properties of nature. The International System of Units — informally known as the metric system — will change in a way that is more profound than anything since its establishment following the French Revolution.
Sometimes I wonder which of my portable digital voltmeters I can trust — the B&K, Fluke, or Amprobe. Usually, they’re pretty close but it bugs me not knowing whether they are right on the nose. Fortunately, these days, there are a number of very accurate voltage reference circuits that you can build or purchase for a few dollars.
Phased arrays have been used for years in military radars for long range detection of missiles. They’re also widely used in military and commercial aircraft radars and some satellites. These phased arrays are expensive, but today thanks to new technology and higher frequencies, phased arrays are smaller and more affordable making them practical for new wireless devices. This article is an introductory tutorial on this special antenna type you need to know about.
Filters are one of the most important and widely-used circuits in all of radio at any frequency. Understanding how they are specified and used will make you a better electronics designer, whether you build your own or simply buy them from a vendor.
A casual observer might think that wireless systems consist primarily of filters connected by the occasional bit of circuit. Block diagrams of transceivers often include as many filters as any other function. This is true at the system level, just as it is at the circuit level — and many circuits behave in a filter-like way, whether intended to be a filter or not! That makes understanding filter basics important for wireless success.
This forth installment will examine the more complex circuits from the “555 Timer IC Circuits” by Forrest Mims. Some will use the PIC replacement from Part 1 (December 2016), while others will develop specific programs using a PIC to emulate a particular implementation of a 555.
For audiophiles, musicians, and ham radio operators, the soft glow of the vacuum tube filament is not only an indication of function, but a nostalgic trigger for memories of simpler times. Though they may have been outpaced by tiny transistors and integrated circuits, these workhorses still may have something to offer in many modern devices.