The thermoelectric effect can be exploited to convert temperature difference to electric voltage or to convert electric voltage to a temperature difference. And devices incorporating the thermoelectric effect can be built and configured to produce heat when voltage is applied. The effect is distinct from resistive (joule) heating, although in actual practice, both effects may […]
Tricks for pulling signals out of noise
Thermal noise, also known as Johnson-Nyquist noise, is generated by thermal agitation of charge carriers inside an electrical conductor or component regardless of any applied voltage. A small voltage can actually be measured across a wire segment that is at non-zero temperature and lying on a non-conductive surface. Apprentice electricians are puzzled by this phenomenon, […]
The difference between CCD and microbolometer thermal imaging
Most engineers are familiar with charge-coupled devices (CCDs) employed as image sensors. Pixels in a CCD sensor consist of P-doped metal-oxide semiconductor capacitors arranged in columns and rows to form an array. Light striking each pixel is converted to an electrical charge that varies according to the light intensity at that pixel. The CCD transfers […]
How to measure display screen output
The flat display screens of today typically look great. But when it comes to quantifying their output, confusion may reign. There are three main measurement tools used to gauge the output of displays. Before we get into their details, it might be helpful to review the main display technologies we are typically trying to measure. […]
The difference between Moore’s law and Edholm’s law
Most engineers are familiar with the observation named after Gordon Moore, the co-founder of Fairchild Semiconductor and Intel, who in 1965 posited that the number of components on integrated circuits had doubled annually and projected this rate of growth would continue for at least another decade. In 1975, looking forward to the next decade, he […]
Choosing the right amplifier
Amplifiers come in all shapes and sizes. The key characteristic of virtually every amplifier is its gain and fidelity of the output relative to the input. Gain, denoted by β (Greek letter beta), is the ratio of output voltage, current or power to input. An amplifier by definition has a power gain greater than one. […]
Music synthesis and arbitrary waveform generators
A pure musical note from a tuning fork is a basic sine wave. The same note played on a trumpet will look like a saw-tooth wave when displayed on an oscilloscope. The same note from a flute will be a triangular wave. But the same note from a clarinet may appear to be closer to […]
Here’s a rundown on free layout/PCB software
There are dozens of free PCB-layout and schematic packages available on the Web. Often they are stripped-down versions of more complex packages available for licensing. Often, the process of upgrading from freeware to more sophisticated versions is pretty easy. If your circuit needs are generally confined to relatively straightforward two-layer boards, here are a few […]
Catch that glitch: Finding race conditions
Among the problems circuit designers have to contend with in their fast and complex electronic environment are race conditions. The term used to be exclusively applied to electronic logic problems but has now been adopted by software engineers working on multithreaded programs. Briefly, software race conditions arise in multithreaded software when multiple threads attempt to […]
Don’t touch that! Things they don’t teach you in circuits lab
The domain of most electronics engineers these days is confined to voltage levels ranging from microvolts on up to a few hundred volts. But when electronic equipment fails or there’s a problem with facility wiring, these same engineers may, in a pinch, be called upon to do basic troubleshooting of power levels far beyond their […]
