This circuit from Popular Electronics powers a small speaker. The transistor can be of general use and the capacitors can be altered to change the sound generated.
We found this circuit in a Poptronics from 1998. The circuit can be extended to more competitors...
We found this circuit in documentation from the National Semiconductor of the 1980s. The circuit...
A configuration like the one used with the 4013 is also suitable for the 4027. The amount of time...