When it comes to high-speed and high-voltage switches, there are many components to choose from – MOSFET, thyristor, IGBT, and even vacuum tubes such as thyristors. But who needs such expensive silicon (or glass) when you only need some pipe fixtures and a lathe to make a high-voltage switch?
At least, this is the method adopted by budget laser experimenter Les Wright in the latest trigger spark gap construction. We have observed his work for some time, especially his transversely excited atmosphere (tea) laser. These lasers are conceptually simple and seem easy to manufacture, at least compared to other lasers. But they do need a fast high-voltage pulse to pass through their long parallel electrodes to the laser, and the control pulse is where the triggered spark gap emits light.
The spark gap is made of brass tubes at both ends of the short PVC connector. [Les] used his lathe to insert a wire into one of the covers to receive the spark plug, and the central electrode of the spark plug passes through a small hole in the metal cathode. In order to trigger the spark gap, [Les] has manufactured a trigger generator with an output voltage of about 15000 v. in a low-pressure nitrogen environment, the generator emits an arc from the spark plug electrode to the spark gap cathode. A small spark will produce a large spark, which will discharge a capacitor on the laser electrode, and you get a controllable single pulse laser. Please view it in the video below.
To be honest, the more we see [rice] videos, the more we want to play laser and high voltage. From DIY door handle caps to bombarding Bayer arrays with cheap CCD cameras, there are always some interesting things in [Rice’s] Lab – and a little dangerous.