This circuit allows single coil switch machines to be controlled using a NO push button switches.
The circuit uses a resistor limited, dual, or split, capacitor discharge switch machine power supply. Current blocking supplies will also work. The capacitor section can drive any number of switch machines.
The only limitation for this circuit is the charging rate of the capacitors.
The following circuits use single capacitor discharge power supplies but are more complex.
The first circuit uses DPST push buttons which are more expensive and are only available in a few styles.
The second circuit uses SPST bush buttons and SCRs to control the power to the coil. The circuit works but is complex.
The next circuits use N+1 capacitors to power the switch machines. This is an economical arrangement and every switch that is in the normal position adds to the capacitance of C1 so in most cases there will be plenty of power for the switch machine coils.
The handle of the toggle switch can be used to indicate the selected track route.
A DPDT switch can also be used, allowing the second set of contacts to be use for frog power control or signals.
The value of the capacitors in the circuits is only a guesstimate. Smaller values may work equally well for a particular switch motor.
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.
30 November, 2017