A Much More DYI Air Gap Flash Unit

In reaction to the other air gap flash unit we featured a few days ago, [Eirik] sent us a tip about another one he recently made. In his setup, the duration of the flash peak intensity is around 300ns (1/3,333,333 of a second). As a reminder, an air flash unit consists of a circuit charging a high voltage capacitor, a circuit triggering a discharge on demand, a high voltage capacitor and the air flash tube itself. The flash tube contains two wires which are separated just enough to not spark over at max potential. Isolated from the other two, a third wire is placed in the tube. This wire is connected to a trigger/pulse transformer, which will ionize the gap between the two capacitor leads. This causes the gap to breakdown and a spark to form, thereby creating a flash of light.

[Eirik] constructed his flash tube using an olive jar and a glass test tube. As you can see from the (very nice) picture above, the spark travels along the glass test tube, making the quenching much faster than in an open air spark. [Eirik] built his own high voltage capacitor, using seven rolled capacitors of roughly 2nF each made with duct-tape, tin foil and overhead transparencies. For ‘safety’ they are stored in a PP-pipe. A look at the schematics and overall circuit shown on the website reveals how skilled [Eirik] is, making us think that this is more a nice creation than a hack.

Disclaimer: As with the previous airgap flash, high voltages are used here, so don’t do this at home.

Making an Airgap Flash

[Maurice] and his team just finished the airgap flash they’ve been working on for a year now. This kind of flash is useful for very high speed photography such as photographing shooting bullets. With a duration of about a millionth of a second it is 30 times faster the normal flashes at their fastest settings. In the video embedded after the break, [Maurice] first explains the differences between his flash and a conventional one which normally uses a xenon flash tube, then shows off different photos he made with his build.

Even though this video is a bit commercially oriented, [Maurice] will make another one detailing the insides. In the mean time, you can checkout the schematics in the user manual (PDF) and also have a look at an other write up he made which we covered in the past. We should also mention that trying to make this kind of flash in home is very dangerous as very high voltages are used (in this case, 16kV).

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