0

March 8, 2011 AT 2:25 pm

How smoke detectors work

Bill’s latest video!

Bill takes apart a smoke detector and shows how it uses a radioactive source to generate a tiny current which is disrupted when smoke flows through the sensor. He describes how a special transistor called a MOSFET can be used to detect the tiny current changes.


Check out all the Circuit Playground Episodes! Our new kid’s show and subscribe!

Have an amazing project to share? Join the SHOW-AND-TELL every Wednesday night at 7:30pm ET on Google+ Hangouts.

Join us every Wednesday night at 8pm ET for Ask an Engineer!

Learn resistor values with Mho’s Resistance or get the best electronics calculator for engineers “Circuit Playground”Adafruit’s Apps!


Maker Business — Kickstarter’s Make 100

Wearables — Wig height

Electronics — Test for interference on the cheap!

Biohacking — Know Your Nut Nutrients

Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at AdafruitDaily.com !



2 Comments

  1. Just for clarity: there are also cheaper smoke detectors out there, that rely on optics to detect smoke – but the presented ones are the better…

  2. The cheapest smoke detectors I see are always battery only ionizing units. The optical units can be better depending on the type of fire. Combination units are available too combining optical with heat or ionizing. I think optical is uncommon for residential devices but more common in commercial installations. Optical beam detectors are used in large spaces like gymnasiums and warehouses where they can be located below the ceiling level for earlier detection.

Sorry, the comment form is closed at this time.