https://25120.org/tags/circuit-snippet/ Recent posts in ‘Circuit Snippet’ en-gb Sun, 10 Aug 2025 15:37:15 +0200 https://25120.org/img/rss_brand.png 144 92 https://25120.org/tags/circuit-snippet/ https://25120.org/post/nixie_driver/ Sun, 10 Aug 2025 15:37:15 +0200 https://25120.org/post/nixie_driver/ <p>Nixies are great. Delightfully simple in their principle of operation and absolutely unmistakable in their aura. The hard-to-imitate aesthetics do come at a cost: they are a bit inconvenient to drive from modern electronics.</p> <p>Many tried-and-proven nixie driver circuits can be found online. Using the classic 74141. With individual high-voltage transistors and shift registers. Or multiplexing the nixies to save on driver electronics? Multiplexing of nixies is a controversial topic: while the benefits are clear, many argue that nixies wear out faster due to the high current peaks when multiplexed.</p> <p>This post isn’t about nixie multiplexing, though.</p> https://25120.org/post/lithium_protection/ Tue, 24 Jun 2025 20:17:57 +0200 https://25120.org/post/lithium_protection/ <p>Lithium cells haven’t become the predominant power source for mobile electronics without reason. Circuits for their—very necessary—protection are naturally plentiful as well.</p> <p>One particular weak point of many protection schemes, however, is deep discharge protection. Common practice is to discharge LiPo/LiIon cells no further than 3 V to not risk permanent damage. Yet, most protection ICs cut off only at 2.5 V, and you thus have to rely on additional battery voltage monitoring.</p> https://25120.org/post/hot_or_not/ Sat, 26 Jul 2014 18:38:13 +0100 https://25120.org/post/hot_or_not/ <p>Recently, I needed a simple temperature switch which could withstand 400 °C. A thermocouple can easily manage this but its generated voltage is unpleasantly small. However, it turns out that a ATTiny216A’s integrated differential amplifier is absolutely sufficient for a, albeit not very accurate, measurement. Enough to determine if something is hot or not, at least.</p>