Various simple electronics projects circuits diagrams for hobbyist and beginners . Simple circuits, mini projects with diagrams and description from many electronics categories.
This Electronic canary circuit presented in this circuit diagramis a electronic door bell designed from an modified hartley oscillator with a couple of extra components included. The transformer is a small audio transformer center tapped with an impedance of 1Kohms at 1KHz and the secondary has an impedance of 8 ohms. The R2 and C4 give to this oscillator it's "chirp" sound.
Changing these components alters the frequency of the chirp.
