This circuit is a doorbell with counter, that means it counts how many times the bell is triggered. It uses a chip synthesizer sound, the HT-2811 ms nothing prevents you from using another device sound generator. The HT-2811 reproduces the sound of a "ding-dong" doorbell. Besides this ic, the circuit includes a CMOS 4026 and Display Driver IC which counts the total number of visitors. Electronic Doorbell with Counter Circuit Diag...
