Resistance soldering is an alternative to conventional “pencil” soldering iron, which offers unique capabilities. Resistance soldering is an easy-to-use alternative soldering technique that’s been available for decades and offers many benefits, although it cannot always be used when soldering is required. It leverages the well-known principle of electrical self-heating (I2R dissipation) to create a localized […]
Have you considered resistance soldering? Part 1
Resistance soldering is an alternative to conventional “pencil” soldering iron which offers some unique capabilities. The image of the electrical engineer or hacker bent over and using a soldering iron on a circuit board is a classic visual cliché of TV and movies (Figure 1). In most of these soldering images, the engineer is using […]
Digipots as electronic potentiometers, Pt 3: Enhancements
Digital potentiometers – digipots – are widely used, versatile, flexible, and feature-laden alternatives to classic mechanical potentiometers. In addition to their “hands-off” controllability, digipots offer additional simplicity, design-in ease, and much lower cost than potentiometers. Among their other capabilities: Dual digipots are useful where two resistances must be adjusted independently but especially so when they […]
Digipots as electronic potentiometers, Pt 2: Features
Digital potentiometers – digipots – are widely used, versatile, flexible, and feature-laden alternatives to classic mechanical potentiometers. In a traditional potentiometer, a person’s hand (or perhaps even a small motor) sets the wiper position and thus the voltage-division ratio. In a digipot, instead, a computer and digital interface connect to the digipot IC and establish […]
Digipots as electronic potentiometers, Pt 1: Differences
Digital potentiometers – digipots – are a widely used, versatile, flexible, and feature-laden alternative to classic mechanical potentiometers. Mechanical potentiometers are standard passive components that designers have used for decades in applications ranging from circuit trimming to volume control. However, they have their limitations: their wipers can wear out, they are susceptible to moisture ingress, […]
Breadboards evolve to meet 21st-century design needs, Part 3: The present and near future
The classic wooden breadboard is obsolete, but its name refers to a vital engineering tool that has changed to meet today’s component and design realities. Wooden breadboards are obsolete as platforms for circuits using modern components, of course, and so-called solderless breadboards are also of very limited usefulness. At the same time, the way designers […]
Breadboards evolve to meet 21st-century design needs, Part 2: Recent past and present
The classic wooden breadboard is obsolete, but its name continues to refer to a vital engineering tool that has changed to meet today’s component and design realities. As leaded components such as discrete transistors and low-pin-count ICs in DIP packages came into use in the late 1960s and 1970s, breadboarding technology evolved as well. Among […]
Breadboards evolve to meet 21st-century design needs, Part 1: The “Ancient” Past
The classic wooden breadboard is obsolete, but its name continues to refer to a vital engineering tool that has changed to meet today’s component and design realities. Breadboards have a special place and multiple meanings in the engineering lexicon. So, what is a breadboard? It can be a crude try-out version of a subcircuit to […]
What are reflectionless filters? Part 4: Implementations
Standard filters reflect unwanted stopband energy, but reflectionless filters present a seamless impedance across both stopband and passband which greatly improves performance of the RF signal chain. Filters are an area of intense interest, analysis, simulation, and often physical fabrication along with tests and academic papers. Yet, for hands-on design engineers, it’s important to be […]
What are reflectionless filters, Part 3: Basic principles
Standard filters reflect unwanted stopband energy, but reflectionless filters present a seamless impedance across both stopband and passband, which greatly improves performance of the RF signal chain. Beginning in 2011, Dr. Matthew A. Morgan of the National Radio Astronomy Observatory (NRAO) in Charlottesville, West Virginia, working with Tod A. Boyd and later with Wavley M. […]
