My first time ever playing with tunnel diodes, believe it or not 🤷🏼♂️😂
They start conducting immediately, but not much, then suddenly crossing some current level, they switch on super-fast, this one is measured in nanoseconds!
Decreasing the current they’ll eventually switch off again, equally fast, delivering a Schmitt-Trigger response.
They’re sensitive devices, you can damage them by using a diode tester on the multimeter, so be careful. They’re also ESD sensitive, so make sure to use a grounding wristband 🙂
There’s just the one component, the LED. Visible through the clear plastic housing, there’s a small black dot, it’s the control chip which makes the LED flicker like a candle.
Measuring the light output with an external detector, it’s clear that while it’s ON most of the time, occasionally it turns off at a seemingly random pattern. And zooming in, it’s clear that it is pulse-width-modulated at different duty cycles, giving the visible effect of a real candle.
It’s actually really smart thought out - that little black chip is a lot more complicated than you’d initially imagine 🙂
I decided to log the mains grid frequency for a full 24hr period 🤷🏼♂️🤓
Using the Philips PM6669 and an external OCXO (calibrated, see earlier post when I received it) I get a quite accurate result. Each measurement takes 10 seconds, so in reality there’s some averaging going on right there, removing some of the jitter and noise at those last digits. The grid frequency is highly dynamic once you reach a millihertz resolution, and that is in fact what I’m trying to capture 🙂
The PM6669 counter has a really nice feature btw., it’s max input level is 260Vrms! That’s really handy, in reality I could connect it straight to a mains outlet without damaging it, but due to the risk of transients I’m using a small transformer and the cute little Vellemann oscilloscope training kit so I can pick a more safe 12Vrms instead 👌🏻⚡️🙂