Build a One IC Based One Chip Chime Circuit Diagram. This circuit uses only one IC, produces a pleasant tone, and sports a single control for adjusting the tone`s chiming rate. IC1A and IC1B form an astable multivibrator, which produces the circuit`s basic tone.
The multivibrator`s frequency is: The component values produce a 668-Hz tone. IC1C buffers the multivibrator`s output to the 8- speaker. Current-limiting resistor R2, determines the speaker`s volume. R2 minimum value is 220 . IC1D and IC1E form an asymmetric, astable multivibrator, which adds a chime effect to the circuit`s basic tone.
The chime effect`s frequency is: R7 gives this rate multivibrator a slowly varying output signal to produce a pleasant decay for the chime effect. IC1F is an inverting amplifier for the chime multivibrator.