The Hubble telescope, despite its initial optics crisis, was an enormously successful undertaking that answered far more questions about the universe than originally posed. Now comes the Webb space telescope, the most powerful telescope ever put into space and a successor to Hubble. If successful, it will look farther back in time, image fainter objects […]
Measuring CMOS power use
Virtually all digital, analog and mixed-signal ICs are now done in CMOS due to the technology’s extremely low power consumption, small size and immunity to noise. Low power consumption arises from the use of a two-transistor configuration resulting in zero power consumption except during brief transitions. Interestingly, the bulk of CMOS power dissipation arises because […]
Measuring resonance with a scope and signal generator
One of the first things EE students learn in their ac circuits course is resonance. Electrical resonance, to quickly review, arises in an electric circuit at a frequency called the resonances frequency when the impedances or admittances of circuit elements cancel each other. In some circuits, resonance happens when the impedance between the input and […]
Gauging the thermoelectric effect
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 […]
