Engineer In Wonderland

Impedance, inductance, permeability, reluctance and electret. All words coined by the largely un-sung Oliver Heavyside, who was also responsible for rearranging Maxwell’s many equations into the classic four, and many many other things. Hats off to a very intelligent and far-seeing human.

Trying to get a circuit to sense its own current consumption can be a little tricky. That said, there are plenty of specialist three and four terminal chips that will sense across a resistor in the positive rail and transfer that to a oV-referenced voltage or current. But for the sake of argument, how about sensing across resistors in the ...

TSZ12x is a series of low-power precision operational amplifiers from STMicroelectronics, offering 8µV input offset (max -40 to 125°C, 5µVmax at 25°C). Chopper stabilisation means drift is virtually zero, and supply rail noise rejection is included (see below). Update (Sept23): ST introduced AEC-Q100 automotive-qualified versions with 4kV HBM ESD: TSZ181H1 and dual TSZ182H1, working over -40°C to +175°C. “At lower die ...

I got a free roll of ABS with a 3D printer I bought recently. It is natural colour ABS (acrylonitrile butadiene styrene). ABS, I believe, was one of the original 3D print filaments. It has a reputation for being strong and resistant to temperature (but not to UV, you need ASA (acrylonitrile styrene acrylate) for outdoor use), but also for warping ...

I had vaguely heard of cryogenically-treated steels, and no more than that. If I though of it at all, it was that maybe it meant dipping it really hot into something really cold. This is sort of right, except that the time gap between the steel being very hot and dipping it into something really cold can be years, and ...

Prusa has announced a 3D printer with a 180 x 180 x 180mm build volume. The firm, based in Prague, has walked-the-walk for several years, using 500 of its own filament deposition printers in a farm that prints the structural plastic parts of those same printers – of which it has shipped ~130,000. As such, the larger existing design, called ...

I saw something new the other day. Someone had parked a shipping container in a street (as you do) and a lorry came along to collect it. It has a pair of hydraulic cranes on the bed, one at each end, and these reached out sideways to pick up the container. While this was happening, other parts came out to ...

When architects draw new buildings, there are often a whole bunch of trees in the forecourt – trees that never quite make it into the finished article. But this is not true of Milan’s vertical forest – the Bosco Verticali – which has so many trees up its sides that even the photos look like artist’s impressions. The designer was ...

Would you believe it, the ESP32 popular Wi-Fi and Bluetooth chip has a built-in Hall effect sensor. Espressif Systems makes the chip, and its ESP32 data sheet has nearly no mention of the Hall sensor – this is the longest and most detailed section: 4.1.3 Hall Sensor ESP32 integrates a Hall sensor based on an N-carrier resistor. When the chip ...

Alex Kenis has taken a deep dive into the technology of the sub-miniature micro-switches used in computer mouses, in a video that taught me things about switches that I have never even considered. It is well worth a look – don’t be put off by the heavy rock intro (the presenter is also a musician) or the somewhat disorganised style ...