Spark gap or knob coherer, 1889

Made:
1889 in England
maker:
Unknown

Creative Commons LicenseThis image is released under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence

Buy this image as a print 

License this image for commercial use at Science and Society Picture Library

Creative Commons LicenseThis image is released under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence

Buy this image as a print 

License this image for commercial use at Science and Society Picture Library

Infinitesimal spark gap or knob coherer, unknown maker, England, UK, 1889. Used by Sir Oliver Lodge to first show the
Science Museum Group Collection
© The Board of Trustees of the Science Museum

Infinitesimal spark gap or knob coherer, unknown maker, England, UK, 1889. Used by Sir Oliver Lodge to first show the
Science Museum Group Collection
© The Board of Trustees of the Science Museum

Spark gap or knob coherer, unknown maker, England, 1889. Used by Sir Oliver Lodge to first show the coherer effect and detect electric surgings by closing the circuit of a galvanometer during experiments on lightning guards

Spark gap or knob coherer, unknown maker, England, 1889. Used by Sir Oliver Lodge to first show the coherer effect and detect electric surgings by closing the circuit of a galvanometer during experiments on lightning guards.

This spark-gap coherer, originally used for experiments on lightning guards, was used by Oliver Lodge in 1889 to detect weak electromagnetic waves. Lodge had observed that the knobs or points used as lightning protectors could become fused together when lightning struck nearby. He found that a very weak spark was enough to create the effect, as long as the surfaces were close enough. Lodge used this device in connection with a bell and a battery, to show the effect of electromagnetic waves. He called this device a coherer, a name which was subsequently applied to all detectors where the action depends upon a light and delicate contact.

On display

Science Museum: Information Age Gallery: Cable

If you are visiting to see this object, please contact us in advance to make sure that it will be on display.

Details

Category:
Radio Communication
Object Number:
1924-36
Materials:
brass (copper, glass, textile, zinc alloy)
type:
coherer
taxonomy:
  • component - object
  • radio receiver
credit:
Donated by Mr. Oliver Lodge [Grandson of Sir Oliver Lodge]
status:
Permanent collection

Cite this page

Rights

We encourage the use and reuse of our collection data.


Data in the title, made, maker and details fields are released under Creative Commons Zero


Descriptions and all other text content are licensed under a Creative Commons Attribution 4.0 licence

Using our data

Download

Download catalogue entry as json

Our records are constantly being enhanced and improved, but please note that we cannot guarantee the accuracy of any information shown on this website.