Posts

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  What happens when you combine a caravan, Home Assistant, 43 gas bottles and a year of weather data?

  Oct 31, 2026

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  by

  Andrew

  in Uncategorised

  Over the past year I’ve recorded every time I connected a new 11 kg gas bottle to my caravan, including the exact date and time. At the same time, Home Assistant recorded the outside temperature throughout. With these two datasets, I could look at the relationship between outside temperature and actual gas consumption. I got…

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  10 MHz Crystal Oscillator – Schematic and Build

  Oct 31, 2026

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  by

  Andrew

  in Builds, DIY, Schematic

  The circuit has been built and tested on the bench. Below are some measurements from testing different component values and operating conditions. R5 – Emitter Resistor R5 = 30 Ω 4.74 Vpp 5.90 V min 10.64 V max R5 = 200 Ω 2.17 Vpp 7.63 V min 9.80 V max Interestingly, the lower-amplitude waveform looks…

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  How well can a current mirror made from ordinary discrete transistors perform?…

  Oct 31, 2026

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  by

  Andrew

  in Builds, DIY, Engineering Education, Schematic

  – Only 11 µA difference between the reference current and the output current – – that is what I measured with a symmetric Wilson current source mirror built from ordinary, unmatched 2N3906 PNP transistors. For the experiment, I used: * 4 randomly selected 2N3906 PNP transistors * 2 randomly selected 18 Ω resistors * Both…