This circuit is designed to simulate the 'Zero Stretching' function of Digital Command Control systems used by model railroads.
This circuit was used drive the booster while testing the operation of block occupancy detectors and DCC signal failure circuits while in the zero stretching mode.
The parts values have been calculated to give the maximum stretching length and ratio allowed for DCC systems. Complimentary outputs, A and B, are provided in order to drive the booster's output polarity stretched in both directions.
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.