Signal generators are devices used to make the signals used in testing and troubleshooting of radio receivers and other circuits, so are of primary interest to almost everyone interested in electronics.
In the US, the DC volt is legally defined by the Josephson array — a super conducting quantum device with a highly repeatable output voltage. Banks of standard cells and temperature-stabilized zener diode references are used by the National Institute of Science and Technology (NIST) to calibrate DC meters for scientific and industrial customers. So how is the AC volt defined?
How many times each day do you pick up a probe to measure a DC voltage? The meter reads, say 4.65 volts, and we usually accept it without question. But just what is a volt and how is it maintained? Here's a fascinating look at the search for increasingly more accurate methods of building a “standard volt.”
It’s not all that often that a different piece of hardware comes along that immediately captures the attention of the builder community. The ESP8266 is an example of this. It’s only about the size of a nickel, yet contains a powerful 32-bit microcontroller and a Wi-Fi interface, plus you can buy it for under $10.
The Raspberry Pi represents a breakthrough in low cost computing power. Get a piece of this popular DIY action by learning how to cook up your own RPi to start experimenting with.
Perhaps one day soon we’ll have a battery that displays no “memory” effect; can be completely discharged or overcharged without harm; and require no complex computerized management system. Does such a battery sound like too much to hope for? Thomas Edison didn’t think so.
As an experimenter, I use wall warts all the time to power circuit boards, microcontroller boards, and even finished projects. However, during the checkout phase of a new circuit, wall warts present a problem. How do you measure their output when they’re plugged into a board or project box?
Electronic designers are familiar with the apparent perversity of Nature in the tendency of amplifiers to oscillate and oscillators to amplify. But even the beginning designer knows that questions of oscillation and stability involve feedback — that ubiquitous structure in natural systems and many man-made ones — whereby a fraction of the system’s output energy is fed back to the input to produce useful effects.
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