How a Simple Spring Changed Light Switches Forever

Summary by Krater

The video explores the history and evolution of light switches, detailing how John Henry Holmes's spring-based design and subsequent innovations like rotary, mercury, and toggle switches shaped modern home electrical systems.

From the video

Answers: How do light switches work and how have they evolved over time?

• light switch history
• electrical circuit design
• rotary switches
• toggle switches
• mercury switches

What it concludes

• John Henry Holmes invented a spring-based electrical circuit closer in 1884 that revolutionized light switch design.
• Early knife switches produced dangerous arcing and shortened switch lifespans, prompting the need for spring mechanisms.
• Mercury switches were discontinued in 1991 because mercury is toxic and dependent on gravity, limiting their orientation.
• Modern light switches utilize simple spring mechanisms and rubber pads to balance durability, cost, and sound.
• Light switches have steadily improved in safety, simplicity, and affordability over the past century.