Simple doorbell Using UM66

Below is a simple circuit of doorbell using UM66. The circuit can be assembled in a general purpose PCB and enclosed in any toys.



C1 – 220 µF 10v
VR1 – 100 k pot
VR2 – 10 k pot
T1 and T2 – BC548
IC1 – UM66

Speaker – 8 ohms
Power – 3v

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