April 2009

Fixing a Tesla coil

April 6, 2009

All of a sudden my DRSSTC Tesla coil stopped working. It took a long exposure in a darkened room to see the very faint corona around the top of the primary coil – that’s definitely not right. The coupling between the secondary and primary coils was too tight. So I rewrapped the primary coil tighter [...]

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Gated oscillator with 4093 chip

April 5, 2009

I recently came across a bunch of 4093 chips: These are Quad NAND gates, with Schmitt trigger inputs. It turns out you can use these to make oscillators and monostables – just like the 555, but more compact with less parts. So I updated the oscillator application I wrote to calculate out values using this [...]

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…and that’s as close to guarantee of satisfaction as you can get.

April 2, 2009

I just watched The Long Good Friday – I’d forgotten about the X classification. That means it’s really, really good. Or something…

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