The Cranky Sysadmin A world of technology, fun, and ignorant rants.

April 3, 2014

Blink an LED with a 555 timer.

Filed under: simple_projects — Cranky Sysadmin @ 8:46 pm

I’ve added a new category, simple_projects for things like this. I may break this out into its own web page if the blog gets crowded. Find the latest simple project below the fold.

Below is the schematic of this simple project and a demo video. Wikipedia has a good article describing the venerable 555 timer. you can change the speed of the LED blink by adjusting the values of R1, R2, and C1. From the article, the LED on time is ln(2)*(R1+R2)*C1. The off time is ln(2)*R2*C1. R1 and R2 are measured in ohms. C1 is measured in farads, so be sure to multiply by 10^-6.

555_astable_schem

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