A September 2008 paper in the IEEE Sensors Journal, outlined sensor applications for early warning systems for bioterrorism. This effort was targeted at viruses with the ability of rapidly spreading in humans during a pandemic. Variants of such pathogens are difficult to detect, so a reliable detection strategy that could classify viruses from innocuous, harmless proteins is demonstrated in this article.

I am not an expert in this field, but I have to believe that this kind of detection process must have some use in our current COVID-19 pandemic. For all I know, maybe a similar technology is already being…

(Image from Keysight)

I want to share some of my design experiences regarding the usefulness of the dB in engineering designs. It’s obvious that engineers work with numbers daily; some of these numbers may be quite large. In many of these cases we are able to use ratios of two numbers.

The dB

The base 10 logarithm begins out journey into what the dB is. It is actually a ratio of two power levels, and so is a quantity without any dimensions. The industry has named the units of dB as ‘Bel’, after Alexander Graham Bell, the telephone inventor. The decibel is commonly used in…

(Image from Littelfuse)

So, you’ve just designed and tested your power supply and it works really well. It meets all of the required system needs and is ready to go. But wait! What about protection from that nasty environment out there in industry? Things like short circuit, overload, voltage transients from lightning, ESD, and other sources are waiting to destroy your new power design.

AC Mains

Let’s start with the AC mains input. This is usually 120 to 250VACrms. Figure 1.

Thermistors come in all shapes and sizes Photo by SSPL/Getty Images

The Thermistor

Thermistors are solid state beasts with a variable resistive element whose resistance changes with temperature; essentially a thermally-sensitive resistor or thermistor. These devices are typically constructed in a two-terminal ceramic bead, glass-encapsulated device or disc configuration made from semiconductor-based metal oxides that have a sintered or metallized leads. When hermetically sealed, resistance reading errors in the presence of moisture are eliminated.

Note that thermistors come in two main varieties:

  • Negative temperature coefficient (NTC) devices that reduce or decrease their resistive value with respect to the operating temperature changes around them. These are most commonly used in designs.
  • Positive…

Beyond capacitors, resistors, and capacitors, one of the most fundamental electronic devices is the Operational Amplifier, or Op Amp. These devices are used for signal conditioning, filtering, obviously amplification, and can even be used to multiply and divide in analog computers.

One key feature of an Op Amp is the differential input, and when put together in a circuit, this can form a virtual ground. The virtual ground concept is helpful for the analysis of Op Amps. This concept makes Op Amp circuit analysis much easier.

An Op Amp inverting input (-) is at zero potential (A virtual ground), even…

I was really touched by the ingenuity and creativity of all involved regarding the technical idea and development of a low cost, fast turnaround medical ventilator. A device like this would undoubtedly save countless lives of people with severe respiratory complications due to the corona virus.

An example of a simple, manually operated ventilator used in hospitals (Image from Ambu USA)

I recently sat down with Aaron Tucker, a Lab Supervisor/Technical Development Coordinator at the Earl E. Bakken Medical Devices Center. He gave me an excellent overview of how this program began and progressed. I asked Aaron some questions which I thought would help explain the thinking, design and technology that went into this project:

A multiplying digital-to-analog converter (DAC) is an important subset of the general DAC family. This useful beast is unique to the general DAC family in that it uses a variable reference voltage. The architecture implements an R-2R ladder configuration where VREF sets the full scale output current, IOUT. (Figure 1).

Figure 1 The simplified R-2R DAC circuit where VREF can be +/-10V (Image from Analog Devices)

Now we add an external operational amplifier, Op Amp A1. The internal RFB (Figure 1) enables temperature tracking for the voltage conversion when combined with the external Op Amp A1 (Figure 2)

Original ‘breadboard’ concept (Image from ScienceBuddies.org)

When I was a fledgling engineer, at 8 years old, I built my first electronic circuit — a very basic crystal radio. Fortunately, at that time, I had the distinct advantage of doing this with a Heathkit crystal radio project that I found as a young boy. When I built this simple radio receiver and was able to tune a single radio station channel in and hear the broadcast via an ‘earphone’, I got ‘hooked’ on a life of discovery and designing/building circuits.

My first engineering manager told me that before I even build a prototype breadboard, the circuit had…

One of the most accurate ways to measure anything is with a Wheatstone bridge. This circuit is just four resistors connected along the legs of a square, and is used in everything from voltmeters to huge industrial scales. Let’s dive into what a bridge is, and how you can design with it.

The basic principle of bridge sensors: If we know the value of three of the resistances R1, R2, R3, and the current shown in the cross branch is zero, the remaining fourth resistor R4 can be found. Zero current can be measured accurately via a galvanometer which will show when the current goes to zero as R4 is varied. (Image from Texas Instruments)

The single-point bridge sensor

If we assume that nominally RG is roughly equal to R1 where all the R1 resistors are equal and tightly matched in value, then this is a typical bridge sensor.

(Image from PsychGuides.com)

The industry seems to be abuzz about some mention of 5G delays in various press and company announcements. Actually, this should only really bother the wireless companies and others who will be making more money with the move to 5G. Let’s face it people — -we’re addicted to our smart phones! We need our 5G fix! We have nomophobia!

I personally have been a part of telecom transitions in our industry when 2G base station digital technology replaced the older 1G analog technology called Advanced Mobile Phone System (AMPS), in which cell phones needed a modem at 9.6 kbps, and…

Steve Taranovich

BEEE NYU, MSEE Brooklyn Polytech, Eta Kappa Nu Honor Society, IEEE Educational Activities Chairman, Electronics Design Engineer 40 years, Tech writer 9 years

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