Thermometers often come in handy when you're feeling ill. Gone are the days when medical thermometers were made of glass and contained mercury, today they're made of plastic and contain a silicon chip.

This a common, modern electronic thermometer. This particular one is made by a German company called Geratherm, but similar models are made by dozens of manufacturers.

This is what we find inside. A single circuit board with just one chip and a few external components. On the right are the contacts for the on/off button, and on the left it connects to a speaker. The actual temperature sensor (located in the tip of the thermometer) is attached to the circuit board through two small wires that connect on the back.

And this is the chip in its entirety. Note that it uses aluminium bondwires rather than gold ones, which unfortunately are not as resistant to the decapsulation process and give off lots of black junk. Still, we can clearly see the circuits, which are mostly digital. That makes sense, because the only thing this chip has to do is convert the analog voltage from the sensor to a digital value and display it on the screen.

Zooming in a bit more, we can see that this chip uses two layers of metal (yellow and white). There are a few large transistors here, probably to drive the speaker, since that uses a lot of current. The LCD display uses very little current, and therefore doesn't need large transistors.

Here we see a lot of parallel wires going around a corner. This could be part of the A/D converter, or perhaps some address decoder in the LCD driver.

The only text or graphic found on the entire chip is in this corner: the number "205" plus identifiers for each photomask. No sign of the manufacturer, so we're left guessing who made this chip.