IR cameras can help size up the surface temperatures of electronic components, PCBs, and other objects to reveal unseen problems. ALAN J. LOWNE, SAELIG CO. INC. Thermal imagers, also called infrared cameras, capture a 2-D representation of objects in front of their germanium optics (ordinary optical glass impedes IR wavelengths). They present a visible version […]
Functions and features of advanced hipot testers
Modern instruments help to check whether manufactured equipment meets the proliferating variety of international safety standards that govern factors such as grounding and the ability to withstand overvoltages. KEVIN CLARK, VITREK, INC. Electrical safety testers – often referred to as hipot testers – are an integral part of electrical and electronic equipment manufacturing. Hipot testers get […]
Understanding fiber optic measurements
Optical fiber is a highly efficient transmission medium for light. Slightly thicker than a human hair, optical fiber is manufactured by drawing out transparent plastic or glass into long strands. It is flexible, capable of bending around obstacles and being fished through small wall cavities. Light travels along straight paths unless influenced by an outside […]
How To Measure Entropy
It was once widely taught that entropy is a measure of disorder. Educators increasingly feel that the concept of entropy as the disorder can be confusing. So increasingly the “disorder” explanation is giving way to the idea that entropy describes energy spreading out or dispersing. The usual ways energy spreads out is when the system […]
Measuring earth’s magnetic field
Earth’s magnetic field is far stronger than that of Venus or Mars, and this single fact explains why life on earth is abundant while its nearest neighboring planets do not at present support life. Earth’s magnetic field extends from its outer core (where swirling molten iron produces a dynamo effect) up through the magnetosphere, extending […]
The difference between arbitrary function generators and arbitrary waveform generators
Signal generators are subdivided into categories that include arbitrary function generators (AFGs) and arbitrary waveform generators (AWGs). The word arbitrary denotes a user’s ability to create waveforms beyond the permanent contents of the instrument’s internal memory. Besides AFGs and AWGs, there are RF and microwave signal generators, pitch generators, digital pattern generators, and more. Typically, […]
Measuring comparator performance; The difference between comparators and op amps
A comparator, as its name suggests, compares two voltages or currents and determines which is higher. The usual implementation is with two inputs for the voltages that are to be compared and a single output that by mean of a logic high or logic low state indicates the higher of the two inputs. Typically, a […]
Measuring pulse-width modulation outputs in industrial equipment
Pulse-width modulation (PWM) is a widely used means of controlling power to large induction motors by means of variable-frequency drives (VFDs). The VFD is capable of varying the speed and torque of an otherwise single-speed ac motor, typically a three-phase 480-V induction motor. Typically housed in a floor-to-ceiling steel enclosure, the VFD modifies the power […]
Measuring polarization
Any treatment of wave polarization must begin with a discussion of the differences between transverse and longitudinal waves. That is because polarization either as a process or a state applies only to transverse waves, not to longitudinal waves. Longitudinal waves are those in which the oscillations are in the direction of propagation. Examples of longitudinal […]
Understanding sampling modes in digital oscilloscopes
In a digital oscilloscope, the analog signal at the input, after attenuation/amplification and preliminary filtering such as for ac coupling, goes to an analog-to-digital converter (ADC). Each channel has a separate ADC, each with an external clock. Analog-to-digital conversion takes place by means of sampling. The samples are taken at specific rates and the amplitude […]
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