A TRANSFORMER TUTORIAL

Theory

The AC Volt

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?

Control

ISaAC — A New Add-on Adapter for the Raspberry Pi

For quite a while now, we have sought the ultimate add-on interface board to enhance some Raspberry Pi (RasPi for short) projects we want to pursue, including a mobile webcam and a wireless sensor network. For such projects to work, it's essential that our RasPi add-on meet several particular criteria.

Wireless

Build Your Own Induction Charger

As an avid hobbyist, I wanted a convenient way to recharge my battery powered projects without having to tie up the USB ports on my computer. Borrowing from the concept of the wireless chargers on the market, I decided to build my own. So if you like the idea of having a wireless replacement for your USB port, open up your surplus parts drawer and let's start the induction process.

Data Acquisition

A Recording Radiation Counter

Are you exposed? Build this unit to detect and display levels of radiation, plus you can record months of data to keep track of just how toxic areas may be or become.

Alternative Energy (Green)

Build the Solar Sequencer

Build a solar sequencer that enables a single solar panel to charge multiple batteries of different sizes and capacities, keeping them isolated from each other.

Workbench

Build a Wall Wart Power Monitor

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?

Stand-Alone Watchdog Timers

Watchdog timers are an excellent way to insure that a microcontroller-based system continues to operate unattended if occasional failures occur. These circuits monitor the operation of the microcontroller and its software and restart it if a problem is detected.

Theory

Video Basics

Although there are many variations and implementation techniques, video signals are just a way of transferring visual information from one point to another. The information may be from a VCR, DVD player, broadcast channel, cable television, satellite system, the Internet, or one of many other sources.