The following is a simple timed DC throttle that has controls for the length of run, accelerate/ decelerate and the maximum train speed. The circuit also has automatic current limiting.
An ideal power supply fo this circuit would be a AC wall adapter. This would likely be less expensive than building a power supply from scratch. The 7812 voltage regulator would not be needed if an adapter with a built in regulator is used.
The explanations for the circuits on these pages cannot hope to cover every situation on every layout. For this reason be prepared to do some experimenting to get the results you want. This is especially true of circuits such as the "Across Track Infrared Detection" circuits and any other circuit that relies on other than direct electronic inputs, such as switches.
If you use any of these circuit ideas, ask your parts supplier for a copy of the manufacturers data sheets for any components that you have not used before. These sheets contain a wealth of data and circuit design information that no electronic or print article could approach and will save time and perhaps damage to the components themselves. These data sheets can often be found on the web site of the device manufacturers.
Although the circuits are functional the pages are not meant to be full descriptions of each circuit but rather as guides for adapting them for use by others. If you have any questions or comments please send them to the email address on the Circuit Index page.