Engineer In Wonderland

I was digging around in the LM311 (and LM111, LM211) comparator data sheet, and came across this unusual voltage reference (diag right). It consists of an npn cascsode pair of transistors, the top one connected (collector to base) as a diode, and the two bases tied together. I have no idea how this works, and am going slightly bonkers trying ...

TI updated the LM339 family of comparators a few years ago, when it moved them from a 150mm wafer manufacturing process to 300mm high-voltage junction-isolated process. These comparators, which come in quad, dual and single versions, were initially released 50 years ago with such a good design – they were the first ‘single-rail’ types which included the 0V rail in ...

The LM334 is not only an adjustable current source, but it is also a rectifier. Right on the front page of the TI data sheet are the words: “Reverse applied voltages of up to 20V will draw only a few dozen microamperes of current, allowing the devices to act as both a rectifier and current source in AC applications.” Which ...

Oh what a delight when an interesting email drops randomly into the inbox. Apparently, Mammoet is assembling the world’s biggest land-based crane at Westdorpe in the Netherlands even as I type. SK6000 is a ‘ring crane’, sitting on a circular track, and able lift huge weights around over large areas – and it looks like separating the counterweight allows for ...

Shenzhen MilkV Technology has a chip that combines: 1x 1GHz C906 RISC-V CPU 1x 700MHz C906 RISC-V CPU 1x 1GHz Arm Cortex-A53 CPU 1x 8051 CPU 1x 1Top/s (INT8) neural processor Called SG2002, it also has 256M (byte, probably…) DRAM, a camera interface, video acceleration, an audio codec and a crypto engine. Peripherals include 100Mbit/s Ethernet (with a phy), USB 2.0, ...

I was out in the countryside with a partially-obedient dog over the weekend. It spontaneously bolts off, the owner told me, for up to a couple of hours. Why not use a dog tracker? I asked naively. It has one, said the owner, but the tracker does not work without mobile phone coverage – when you get home, you know ...

A few years ago, a friend of mine was trying to build a solar-powered device to automatically photograph the sun in the sky at exactly noon every day through a whole year – the aim, purely for interest, was to create an analemma photograph showing the figure-of-eight that the sun follows as the months progress. At the time, getting a ...

All credit to Thomas Langewouters for an unusual reed switch ladder circuit for liquid level sensing. You can find it on his website here. He went on to use a more traditional two-terminal design, but this four-terminal circuit, as he points out, can be used to get a little more information. Fluid level sensing with reed switches involves a fixed ...

It is spring time, so it must be time to contemplate once more the many challenges of Cuk converters. And this time it is the question: how does one turn on and off a load when the output of a Cuk converter is of the opposite polarity to the input (right). The obvious thing is to hang a p-channel mosfet ...

One of the monomaina’s in Wonderland is ‘building a better pulse generator’, for want of a better phrase. It should be so easy with all the Arduino-esk microcontroller boards out there that have lovely timers inside, but a recurrent drawback is that it is hard to find one that runs at a ‘nice’ frequency – one with a clock period ...