Electronic Chime by IC 4069

This circuit simulates a chime similar to the sound many cars make when the keys are left in the ignition. The bottom two gates form a squarewave audio oscillator that drives the base of the 2N4401, turning it on and off at an audio rate. The top two gates produce a short low-going pulse about once per second that discharges the 10 uF capacitor through the diode.

Read more original source:
http://www.techlib.com/electronics/noisemakers.html

This entry was posted on Friday, June 20th, 2008 at 2:16 pm and is filed under Audio - Alarm. You can follow any responses to this entry through the RSS 2.0 feed.