Doorbells

 

Circuit / Schematic diagram of  Description
   
555 Timer based door bell Timer used in astable multivibrator mode to generate tone
3 Tone Gong Based on SE800 with adjustable speed of melody
Doorbell with Counter Based on a synthesized sound chip from Holtek, the HT-2811.
Electronic Canary (Doorbell) Bell constructed by modifying Hertley Oscillator
Fix Adds Door-Chime Repeater Timer based door bell
Multi-Switch Doorbell with Indicator  
Self-Powered Door-Bell Watcher Allow a person to monitor if someone has rung his home door-bell when he was out.
Remote Doorbell Indicator This circuit will light a lamp when doorbell  switch is pressed
Birdie Doorbell Ringer  
Ding-Dong Bell  
Doorbell for the Deaf This circuit provides a delayed visual indication when a door bell switch is pressed.

 

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