Patent · 1922 · age 66

US Patent 1402025: Frequency meter

Kept from patents.google.com · 1 file · 90 KBCall number TES PT1922.01

Provenance

Source: patents.google.com
Retrieved: 1 October 2026
Source terms (summary): Google terms: automated access against robots.txt counts as abuse
Rights: Public domainPatent text by Tesla, who died in 1943.Basis: author death year 1943, under a life-plus-70-years rule, as of 2026; other rules, such as the United States publication-date rules, are not assessed.
Formats: HTML
Fingerprint: 3a9fa2a2123aa490ccb9d12f3ee8f69d8fc075a8b5ba02cd95aa2ec8bed06fd9sha256 of the file (64 characters). Any change to the file changes this code.
Cite as: Nikola Tesla, US Patent 1402025: Frequency meter (1922). Long Keeping, call number TES PT1922.01. https://longkeeping.com/nikola-tesla/us-patent-1402025-frequency-meter/

Unchanged since collected At the last check, on 2 October 2026, all 903 originals, this work's file among them, matched the fingerprints recorded when they were collected. Each copy is re-checked by hand once a year; there is no automatic alert yet.

Notes on this copy

#2Machine-read text (OCR), not proofread, with no page images in the file to check it against.

Original

googlepatents_US1402025A.html

Open reading copy 90 KB Exact filePublic domain

Reading copy: the saved page with its pictures left out. A picture appears in the reading copy only once the library has recorded its licence, the licence is on the library's pass list, and it has been checked for a likeness. See its pictures at the source (another site). Exact file: the page byte for byte; its pictures do not load here.

Files

First pass, not a clearance.

Links inside these saved pages were written for the site they were saved from; some lead nowhere here.

File	Format	Size	Source	sha256	Label
googlepatents_US1402025A.html exact filemain	HTML	90 KB	patents.google.com	3a9fa2a2123aa490ccb9d12f3ee8f69d8fc075a8b5ba02cd95aa2ec8bed06fd9	Public domainPatent text by Tesla, who died in 1943.Basis: author death year 1943, under a life-plus-70-years rule, as of 2026; other rules, such as the United States publication-date rules, are not assessed.