Posts tagged ‘Circuit Snippet’

Charlieplexing Nixie Drivers

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.

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.

This post isn’t about nixie multiplexing, though.

Lithium Battery Protection for Small Projects

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.

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.

Thermocouple via Integrated Differential Amplifier

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.