engineer-in-wonderland

Rooting around in the fascinating stuff at the bottom of a draw labelled 'Engineering - Junk Miscellaneous'. Delving amongst the delightful...

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Fun in a box

I am not normally one for gadgets, but an amazing little quadcopter has both put a smile on my face and sent me nuts over the past few days.

For a couple of months before GCSE time, I was helping with revision.

This was a pleasure and, I think I…

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Zeta: Yet another dc-dc topology

Call me slow, but I only just discovered the zeta dc-dc power converter topology.

It is a bit like sepic and Cuk, in that the output can be higher or lower than the input.

And that there are two inductors and a series capacitor.

And it is a bit…

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Base emitter ‘Zeners’ don’t have to be 7V

A rule of thumb is that the reverse breakdown voltage of bipolar transistor base-emitter junctions is around 7V.

Wnich is why the transistors in this active bridge rectifier are ‘back-to-front’.

But this does not have to be the case.

For example, the 2SD2704K from Rohm, a transistor…

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More on: low saturation matrix transistors

Much as I have been banging on about low-saturation transistors from Diodes (was Zetex), I have omitted to mention that NXP makes then too.

Here is NXP’s low-saturation matrix transistor backgrounder…

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Mr Kurt inspires a circuit

The wise Mr Kurt*, sometime correspondent of this blog, has been helping someone out with a design.

It is not for me to reveal his intellectual property, but the circuit neatly uses the fewest number of components to get the job done with the voltage available.

In a round-the…

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RFID is not only magnetic

I have found yet another gap in my knowedge (only the 2nd today though) -  I have only been thinking of inductive RFID whch I think battery-free.

Meanwhile, electromagnetic battery-free RFID has popped up – there is a mini-backgrounder on this page from Sky RFID.

Actually, I do temember…

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Phase-locked loop triumph

I have always had a soft spot for phase-locked loops – at least, I have since I first found out what they were.

What I like about them is that they servo into the best answer for a given situation – For example, they can get in there and dig a…

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Why low stand-by in LED drivers?

When Power Integrations announced its LYTSwitch-2 family of mains LED driver ICs last week, an interesting snippet emerged – the firm has designed the driver with stand-by power consumption down at 30mW.

It is designed for used in retrofit bulbs, retrofits for fluorescent tubes, and ballasts.

It turns out…

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Cuk converters, so help me

First thing, it is pronounced ‘chook’, and it is a man’s surname, so it is not CUK.

Really, it has an accent over the C, but I cannot remember what type and I am going to leave it out, with apologies to Slobodan Cuk.

Anyway, the Cuk converter is…

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Used chopsticks into Li-ion batteries

A strategy to convert used disposable bamboo chopsticks into uniform carbon fibers for anodes of lithium ion batteries is described in a Royal Society of Chemistry paper ‘Evolution of disposable bamboo chopsticks into uniform carbon fibers: A smart strategy to fabricate sustainable anodes for Li-ion batteries’.

According to the…

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