mostly used in audio related applications. In this circuit it is wired to produce different sound effects like waterfall, rain, sea waves, wind, river etc. The different sound effects can be produce by using different values of capacitors in the place of Cx. The values can be from 0.1uF to 100uF.
Another chip used in the circuit is a TDA2822M IC. TDA2822M is a low voltage audio amplifier IC available in 8 pin minidip package, it has many good features like low operating voltage due to which it can work till the 9V battery runs down to 1.5V, low quiescent current which increases the battery life many times. In this circuit this IC is used to amplify the output of the MM5837 IC to drive an eight ohms speaker. The volume of the circuit can be adjusted with 10K variable resistor.
Here is an interesting project of a multiple sound effect generator circuit. The circuit is using two ICs, which are MM5837 as IC1 and TDA2822M as IC2. The heart of the circuit is a MM5837 digital noise generator IC. MM5837 is an 8 pin dip package IC designed to generate white noise signals and for