Making a Spherical Audion Tube by Ron Soyland

Another great series of videos from Ron Soyland. In this video he recreates the classic Audion tube invented by Lee De Forest in 1906. The particular tube he creates in this video appears to be similar to the 1909 version of the Audion but substantially better made. The original Audion tubes were usually crudely constructed without the benefit of modern tooling or our current understanding of thermionic emission, they were expensive and had a short lifetime but paved the way for better tubes in the following years.