The choice of power sensor and meter greatly depends on the qualities of the signal being measured. Bob Buxton, Boonton Electronics Today’s complex modulation schemes and pulsed communication modes have brought the need to measure RF power ever more accurately and efficiently. There are multiple technologies available for the measurement of RF power, falling into […]
FAQ
Test and measurement in education
Lab classes become much more meaningful when students can operate their own test instruments rather than watch an instructor turn knobs and push buttons. Paul Cracknell, Liquid Instruments Consider the typical EE lab in the average university. Labs must be outfitted with costly equipment to give students exposure to the breadth of measurements that characterize […]
What are alternatives to Li-ion batteries?
There are many alternatives to Li-ion batteries, including fuel cells, various types of supercapacitors, redox flow batteries, novel Li-based chemistries such as lithium-sulfur (LiS), and more. This FAQ focuses on alternative non-lithium rechargeable battery chemistries, including calcium-ion (Ca-ion), magnesium-ion (Mg-ion), sodium-ion (Na-ion), zinc-ion (Zn-ion), iron-air (Fe-air), and sodium-sulfur (NaS) that can be more readily integrated…
Debugging digital and analog signals with cross-domain analysis
Multi-domain signal analysis is blurring the line between real-time oscilloscopes and real-time spectrum and signal analyzers. Fernando Gomez, Tektronix Inc. Multi-domain signal analysis is enabled by advanced oscilloscope features such as 12-bit ADC, digital down conversion (DDC), and flexible channel inputs where each can be either analog or digital. As Signal Integrity (SI) and Power […]
Can RF shock you?
Engineers know they’ll get a poke if they touch household ac wires. But RF current typically is not felt as electric shock because the frequency is too high to depolarize nerve membranes. However, RF current can cause both internal organ damage and surface radiation burns, so care must be taken to avoid high exposure. It’s […]
Scope-based diagnosis of three-phase motor drives
Ordinary oscilloscopes can view basic parameters in modern motor drives, but operational insights generally require specialized power analyzers. Variable frequency drives (VFD) generate carefully controlled pulse-width modulated (PWM) waveforms to modulate the speed of industrial ac motors. Often, the motors involved are three phase. Three-phase ac induction motors (ACIMs) are widely used though they are […]
Measuring power choke inductances
The inductance of power chokes changes with current level. Conventional small-signal-measuring bridges are out of their depth here! Hubert Kreis, ed-k • Alan Lowne, Saelig Co. Inc. With the exception of air-core coils, all power inductances show a saturation behavior; their inductance drops with rising current. The core materials can lose permeability and then behave […]
With so many mandates, can successful designs still be achieved?
The overlap among best design practices, regulatory mandates, and project requirements may result in conflict and unachievable project results. Engineers are used to designing with respect to constraints and tradeoffs: after all, that’s what design is mainly about. If there were no such tradeoffs, getting a project completed and signed off would be far, far […]
Audio measurements for product development
It pays to know the fundamental parameters that quantify the performance of sound equipment. Daniel Knighten, Audio Precision Quantitative, objective audio measurements have a role to play not just during design validation and as a manufacturing quality control tool, but during all stages of product development . They even come in handy during the earliest […]
What is the controller area network (CAN) bus?
The controller area network (CAN) bus was developed to support the networking of large numbers of electronic control units (ECUs) in automobiles. CAN is implemented using unshielded twisted pair (UTP) cabling, designed for reliability in electromagnetically noisy environments. CAN has evolved significantly since it was first introduced in 1986, along with early ECUs. Today, there […]