The shortage of respiratory ventilators in the face of the Covid-19 pandemic has led to numerous efforts aimed at turning hand-operated plastic pouches called bag-valve resuscitators into makeshift ventilators. The resuscitators, also called Ambu bags, are generally on-hand in large quantities. They are designed to be operated by hand, by trained technicians, to inflate patient […]
Overview of electrical measuring instruments -Part one
Here’s a quick review of some basic instrumentation common to most engineering work benches. Ammeter The ammeter is the basis for many other electrical measuring instruments. Whether you are measuring volts or ohms, essentially inside the instrument you are measuring current. Measurement of current in a circuit is somewhat problematic because all the electrical energy […]
Another Covid causality: The James Webb telescope
NASA has announced it will pause work on the James Webb Space Telescope because of the ongoing COVID-19 pandemic. The launch is still currently on the books for 2021, but there are questions about whether that date will hold. The James Webb Space Telescope, successor to the Hubble and Spitzer instruments, was originally scheduled to […]
How to test for Covid-19 in 45 minutes
The FDA recently authorized use of a fast test for the Covid-19 virus that reportedly can finish up in about 45 minutes. The test was developed by Cepheid, a molecular diagnostics company that is part of Danaher Corp. The beauty of the new test is that it runs on existing Cepheid hardware called the GeneXpert […]
Can you really make a respiratory ventilator in a car factory?
Mechanical ventilators are making headlines these days because of the Coronavirus-19, widely regarded as a flu but which is actually a respiratory disease that attacks the lungs. The key to minimizing the death toll for those with virulent infections is the availability of mechanical ventilators that help people breathe when their own lungs can’t. Reports […]
How the health care system tests you for the Covid-19 virus
Engineers who usually spend a significant amount of their time around test instruments are likely spending more of it at home these days. Those of us whose working life has been interrupted by the Covid-19 virus might well begin pondering about what goes into a test for human viruses rather than those confined to computers. […]
The difference between instrumentation and differential amps
Many of the test instruments used in industry today have inputs based on instrumentation amplifiers. This kind of amplifier, sometimes abbreviated as InAmp, is itself based on a more fundamental amplifier setup, the differential amplifier. It can be helpful to understand how these two devices differ. A differential amplifier ideally amplifies the difference two input […]
The difference between SWR and TDR meters
In setting up transmission lines, it is often desirable to measure the amount of signal reflection. The relevant metric is the standing wave ratio (SWR). SWR is defined as the ratio between the amplitude of a partial standing wave at antinodes [max] to the amplitude of the adjacent mode [min]. Thus a ratio of 1.5:1 […]
Do you really need a VNA when a scalar network analyzer might do?
Network analyzers measure network parameters of electrical networks, such as two-port amplifiers and filters. The instruments characteristically operate at 5 Hz to 1.05 THz, mostly at the higher end, though some models are sensitive down to 1 Hz. These instruments are available in two varieties: scalar network analyzers, which measure only the amplitude of the […]
The therapeutic uses of RF energy
Discussions of the upcoming 5G technology sometimes focus on whether or not the millimeter-wave frequencies involved can damage human life. What gets less press is that radio frequency energy in other bands can be therapeutic. It can be useful to review a few of these uses to understand the beneficial role RF energy can play. […]
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