Computer 74, Teil 5 (Aufbau eines Computers mit TTL ICs 7400)

Many owners of model railways want their world of trains` to be as realistic as possible. A means of imitating the sound of a real steam train is, therefore, more than welcome. This article describes a simple method of building an electronic circuit of few components that will produce the required sound. To add even more authenticity, the rhythm of the steam train sound is regulated automatically and is practically proportional to the speed of the train.