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 […]
The difference between measuring magnetic flux and magnetic fields
Simply stated, a magnetic field is analogous to electrical voltage, while magnetic flux is analogous to electrical current. A magnetic circuit is analogous to an electrical circuit with important differences. Electromotive force in an electrical circuit corresponds to magnetomotive force. Resistance and its reciprocal, conductance, in an electrical circuit corresponds to reluctance and its reciprocal, […]
Practical measurement of feedback loops and their stability
Feedback is relevant not only to electronic circuits but also to all kinds of natural and human-based phenomena ranging from mechanical engineering to economics and finance. Feedback emerges when one or more system outputs are connected back to system inputs. If polarity is inverted, it is an instance of negative feedback, which in electrical circuits […]
Basics of CMOS and measuring CMOS logic parameters
Complementary metal-oxide semiconductor (CMOS) fabrication uses p-type and n-type complementary and symmetrical pairs to implement logic functions. The fundamental building block of the CMOS circuit is the MOSFET semiconductor, which enables it to operate at far lower current levels than bipolar transistors. This current reduction comes via pairs of p-type and n-type MOSFETs connected gate-to-gate […]
Hysteresis and its measurement
Hysteresis might be defined as something that happens when the physical state depends upon its history. The classic example of hysteresis in action is the residential thermostat. It has built-in hysteresis to prevent rapid cycling. It’s low cut-in and high cut-out levels are designed to prevent the heating/cooling system from rapid switching, which would quickly […]
The hot and cold of thermocouples
The common temperature probe contains a thermocouple consisting of two dissimilar metals welded together to form an electrical junction. A voltage that varies with temperature is generated. Slightly less accurate than resistance temperature detectors (RTDs), thermocouples cover a wide temperature range and respond quickly. Combinations of different metals create different voltage responses. All dissimilar […]
Lasers and how to measure their output
Laser is an acronym for light amplification by stimulated emission of radiation. Lasers, of course, started out as comprised of discrete components. The most basic laser consists of a cylinder containing the lasing medium, a material that emits light when exposed to an outside source of energy. The gain medium can be gas, liquid, solid […]
Understanding electro-optic modulation
The electro-optic modulator is used to modulate a beam of light. Laser-controlled modulators are capable of operating in the gigahertz range, and modulation may be imposed on the amplitude, phase, or polarization of the beam. The component that makes this possible incorporates an element that exhibits an electro-optic effect, a change in its optical properties […]
Understanding and measuring optoelectronic oscillators
The problem with even a high-end electronic oscillator–such as a quartz crystal oscillator, dielectric resonator, sapphire resonator or air dielectric resonator–is that as the output frequency rises, excessive phase noise also rises. Optoelectronic oscillators are not subject to this and other dysfunctional high-frequency characteristics, and consequently they are suitable in certain exacting 21st century applications […]
