| # | Country | Total Patents | |
|---|---|---|---|
| #1 | Germany | 45 | |
| #2 | United Kingdom | 2 | |
| #3 | United States | 1 |
| # | Technology | |
|---|---|---|
| #1 | Electric discharge tubes | |
| #2 | AC and DC conversion devices | |
| #3 | Transmission | |
| #4 | Generation of oscillations | |
| #5 | Treatment of glass | |
| #6 | Loudspeakers and microphones | |
| #7 | Semiconductor devices |
| # | Name | Total Patents |
|---|---|---|
| #1 | Johannes Nienhold | 1 |
| Publication | Filing date | Title |
|---|---|---|
| US1434310A | Vacuum rectifier | |
| GB159170A | Improvements relating to mercury-vapour rectifiers | |
| GB142870A | Apparatus for rectifying high and low frequency alternating currents |