Germanium Diodes

Gherkin with germanium diodes

• Gherkin PCB
• Vintage Russian D9K (Д9К) Germanium detector diodes

Old stock Russian diodes. Large clear glass body. You can find these on eBay from multiple sellers.

There is no benefit to using these over a 1n4148 silicon diode in a normal keyboard. They do look very different. The glass is brittle compared to the glass in a 1n4148 diode.

If building something battery powered, the lower forward voltage would keep the matrix functional at much lower voltage levels. Schottky diodes could also be used.

40% Edward keyboard was also built with these.

Some measurements of different diode types in a keyboard matrix