What Is Emissivity? (EE Tip #133)


All objects radiate infrared energy. The warmer an object is, the faster the molecules in the object move about, and as a result the more infrared energy it radiates. The wavelength of this radiation lies roughly between 0.5 and 100 … Continue reading


Measuring Jitter (EE Tip #132)

Figure 4—Time interval error (TIE) is another way to measure jitter. Here, the actual transitions are compared to a reference clock, which is supposed to be “perfect,” providing the TIE. This reference can be either another physical signal or it can be generated using a PLL. The measured signal’s accumulated plot, triggered by the reference clock, also provides the so-called eye diagram.

Jitter is one of the parameters you should consider when designing a project, especially when it involves planning a high-speed digital system. Moreover, jitter investigation—performed either manually or with the help of proper measurement tools—can provide you with a thorough … Continue reading


DIY Single-Board Computer (EE Tip #131)

Photo 2—This is the N8VEM in its $20 stand-alone incarnation. Even without any other boards, this SBC provides sufficient I/O and storage options to be a full-fledged CP/M computer.

In the early 1990s, nostalgic users wrote software emulators to relive the “vintage” experience of their old Commodore 64 or Apple II. Others preferred the actual hardware and began collecting classic computers. As their old machines occasionally broke down, people … Continue reading


Battery Charger Design (EE Tip #130)

Figure 1: This lead-acid battery charger uses Texas Instruments’s UC2906 IC.

It’s easy to design a good, inexpensive charger. There is no justification for selling cheap, inadequate contraptions. Many companies (e.g., Linear Technology, Maxim, Semtech, and Texas Instruments) supply inexpensive battery management ICs. With a few external parts, you can build … Continue reading


Active ESD Protection for Microcontrollers (EE Tip #129)

Figure 2—Typical ESD protection circuit, as found in an Atmel microcontroller

Microcontrollers need to be protected from of electrostatic discharge (ESD). You can use the circuit described in this post when you have an application requires a greater degree of ESD protection than what you get from an IC on its … Continue reading