| Year | 1919 |
| Date | 24-Jul |
| Volume | 41 |
| Issue | 952 |
| Page | 86 |
| Category | Electronic |
| Part | 4 |
| Title | Wireless Notes and Developments |
| Author | J.Scott-Taggart |
| Notes | The Vacuum Valve. Used to amplify signals from a crystal detector receiving circuit, valve used as a detector |