The New Hotness

With the microwave back in operation, I thought I might learn something about the failed gas sensor:

Given that much information, finding the datasheet for a Figaro TGS880 sensor didn’t require much effort. In case you were wondering, the replacement sensor has no trace of branding or identification.

The sensor element has a resistance varying with gas concentration, for a variety of test gases I hope our kitchen never contains in such abundance:

The measurement circuit:

I betcha the microwave waits for an order-of-magnitude resistance drop from whatever the starting value might be, then calls it done.

The belly band holding the steel mesh to the plastic base is no match for a Dremel slitting wheel:

As the saying goes, Sensoria est omnis divisa in partes tres:

A closer look at the sensor element:

The granular surface does not get along well with the 5× digital zoom required to fill the phone’s sensor, but you get the general idea:

The heater measured 30 Ω on the dot and the sensor was an open circuit on the 100 MΩ range. Connecting the heater to a 5 V supply dropped the sensor resistance to 800 kΩ @ 50 %RH and a warm breath punched it to about 2 MΩ. That’s with an ohmmeter because I haven’t yet unpacked the Electronics Bench, but seems far above the spec of 20-70 kΩ in air.

So it’s still a sensor, even if it’s not within spec.

The WordPress AI-generated image for this post is … SFnal:

My pictures apparently aren’t up to contemporary blog standards …