Part 1 looked at the difficult, costly, and lengthy journey from concept to a successful launch. Part 2 looked at the severe problems of the HST discovered after launch, and Part 3 looked at what has been learned from the Hubble “experience.” The final installment of this story looks at the plans for a post-Hubble […]
FAQ
The Hubble Space Telescope: Part 3
Part 1 looked at the difficult, costly, and lengthy journey from concept to a successful launch. Part 2 looked at the severe problems of the HST discovered after launch. Part 3 of this story looks at what has been learned from the Hubble “experience.” There are many lessons from this expensive disaster turned into spectacular […]
Understanding instrumentation for measuring total harmonic distortion
When discussing total harmonic distortion (THD), the fundamental of the wave in question is known as the first harmonic. Quantifying THD, therefore, begins with the second harmonic. Theoretically, the number of harmonics is limited only by some maximum frequency based on minimum quantum wavelength. In reality, however, we are interested in a relatively small number […]
The Hubble Space Telescope: concept, delay, embarrassment, despair, and finally – jubilation, Part 2
Part 1 looked at the difficult, costly, and lengthy journey from concept to a successful launch. Part 2 looks at the severe problems of the HST discovered after launch. Out of Focus: only the most-obvious problem When Hubble’s lens cover was first pulled back, and the imager saw its “first light,” no one expected picture-perfect […]
The Hubble Space Telescope: concept, delay, embarrassment, despair, and finally – jubilation, Part 1
The stunning images taken by the Hubble Space Telescope (HST) (Figure 1) over the past two decades, using a variety of optical instruments and sensors, have transformed our view, literally and figuratively, of the cosmos. But the Hubble’s story is also one of project conception, engineering persistence, joy, misery, embarrassment, improvisation, rehearsal, and eventual redemption. […]
Printed Circuit Boards, Part 4: Beyond FR-4
Part 4 concludes this FAQ with some fabrication issues and at substrates with performance which is multi-GHz-compatible and goes beyond that available using FR-4 material. Q: What’s the set-up situation for PC board fabrication? A: The production-level fabrication process is optimized for runs of tens, hundreds, and thousands of boards, as there is a set-up […]
The super-cold measurement science of superconductivity
Ordinary conductors such as copper and silver exhibit less resistance as the temperature drops. But even near absolute zero they still have some resistance. With true superconductivity, the resistance of certain materials drops to precisely zero when they hit a certain critical cold temperature. This type of superconductivity is a quantum mechanical process that involves […]
Printed Circuit Boards, Part 3: Vias and multilayer boards
Part 1 of this FAQ series looked at the ubiquitous FR-4 PC board as well as other PC board issues, and Part 2 reviewed highlighted some of the board issues and the widely used FR-4 PC board substrate. This third part looks at advanced PB board issues such as vias and multilayer boards. Q: How […]
The basics of FR-4 Printed Circuit Boards
Part 1 of this FAQ provided context and background on the PC board, and discussed its first widespread appearance as a phenolic-based board. Part 2 looks at some board issues and the widely used FR-4 PC board substrate. Q: I see the term “solder mask” — what is that? A: Solder mask (also called a […]
Basic instrumentation for the electronics workbench
Engineers and technicians doing design, development, and testing have a wide range of instrumentation available for use on the test bench. So it might be useful to consider which instruments are considered the “basics” for the general case. Here are a few nominations along with the device properties that are generally considered “must-haves.” The unassuming […]