Using electronic diagram below can be built complementary electronic buzzer ring. This bell buzzer sounds after it was released button ring. Its required energy is stored in capacitor C2 whilst the ringer button is pressed. This adds a small task (and brief) adapter ring. At the same time, ensure blocking of T1 T2. Release the button, T1 and T2 locks begins to run. While there task C2 buzzer will sound. Sound duration depends on the value of C2 (the higher the value, the longer it sound).