Fail of the Week: Cheap Chips Cause Chaos

We all know the old saw: if it’s too good to be true, it probably is. But nowhere does this rule seem to break down as regularly as when we order parts. Banggood, AliExpress, and eBay are flooded with parts ready to be magically transported across the globe to our doorsteps, all at prices that seem to defy the laws of economics.

Most of these transactions go off without a hitch and we get exactly what we need to complete our Next Cool Thing. But it’s not always so smooth, as [Kerry Wong] recently discovered with an eBay order that resulted in some suspicious chips. [Kerry] ordered the AD633 analog multiplier chips as a follow-up to his recent Lorenz Attractor X-Y recorder project, where he used an Arduino to generate the chaotic butterfly’s data set as a demo for the vintage instrument. Challenged in the comments to do it again in analog, [Kerry] did his homework and found a circuit to make it happen. The needed multipliers were $10 a pop on DigiKey, so he sourced cheaper chips from eBay. The $2 chips seemed legit, with the Analog Devices logo and everything, but the circuit didn’t work. [Kerry]’s diagnosis in the video below is interesting, and it’s clear that the chips are fakes. Caveat emptor.

Here’s hoping that [Kerry] sources good chips soon and regales us with a successful build. Until then, what are your experiences with cheap chips? Have you been burned by overseas or domestic suppliers before? Does any single supplier seem like a better bet to you, or is it all hit or miss? Sound off in the comments below.

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