A fuel cell converts oxygen or another oxidizing agent and hydrogen or some other fuel into electricity and heat. A third byproduct, depending on the fuel used, is methane or another non-earth-friendly substance. But the most basic fuel cell combines hydrogen and oxygen to produce pure water. This simple, long-lasting device with no moving parts […]
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Measuring efficiency in solar photovoltaic cells
Single-junction solar cells have a maximum theoretical efficiency of 33.16%, the Shockley-Queisser limit. But there are work-arounds that permit solar array designers to surpass that limit on a square-foot basis. The maximum solar conversion efficiency of around 33.7% happens at a 1.34 eV band gap and is subject to several assumptions. By way of review, […]
Up close and personal with magnetrons
Today most people’s experience with a magnetron is as a source of microwaves in residential microwave ovens. The microwave radiation is conveyed to the oven section via a waveguide. Microwave ovens are also a favorite target of scavengers and experimenters who like to take things apart. The magnetron is one frequently scavenged component. You can […]
The back and forth of interferometer technology
Conceptually, the interferometer is a relatively simple instrument that compares two distances typically differing only by a slight amount. Two waves, often coherent light waves, reflect from standard mirrors mounted at the object under investigation. The light from one mirror passes through a half-silvered mirror while the light from the other reflects from the back […]
Difference between measuring resistance and conductivity
Generally, an electrical conductor is a long solid rod, often insulated. It may be rectangular, like the electrician’s bus bar, irregular in cross section, or it may be merely a conductive path through the atmosphere, created by a process of ionization. Most electronics professionals have measured the resistance of conductors typically using a volt-ohm meter. […]
Are you sure you know what bandwidth means?
Bandwidth is a principal specification when choosing an oscilloscope or related instrument. What it means in this context is a displayed signal’s maximum frequency above which the scope attenuates the amplitude of the signal it sees. Problem is, this isn’t the only definition of bandwidth. The concept has slightly different meanings (and consequences) depending on […]
Subtleties of math functions in digital storage oscilloscopes
One of the great innovations in modern oscilloscopes is the Math mode. Even in many inexpensive scopes, it generally takes three forms: Dual Waveform Math, FFT, and Advanced Math. Dual Waveform Math requires two waveforms displayed in separate channels to function, but aside from that, it is quite simple. You just run a couple BNC […]
Working with oscilloscope probes, part two
The oscilloscope can be viewed as essentially a voltmeter that incorporates a dynamic display. But the oscilloscope can also make use of a current probe to convert current information into corresponding voltage potentials displayed in units of Amperes. The current-to-voltage conversion takes place within the current probe which operates like the electrician’s clamp-on ammeter. The […]
Basics of oscilloscope probes – Part one
Engineers know what an oscilloscope probe is. It basically permits the user to measure the voltage at any terminal or wire and display the waveform. It usually incorporates a needle point that is capable of getting into a tight place without shorting out to another pin, wire or grounded surface. And it can be equipped […]
A fractional Fourier Transform? Yes, there is such a thing.
The Fourier Transform, outlined by French mathematician and physicist Joseph Fourier (1768-1830) in The Analytic Theory of Heat (1822), asserted that any function of a variable, whether continuous or discontinuous, can be expanded in a series of sines of multiples of the variable. His focus at the time was the propagation of heat in an […]