This is a one module of diesel and horn train circuit. This circuit is work with built by 555 timers IC, and some op amp. This circuit is a complete system for the horn circuit. This is the figure of the circuit.
The main power supply to the system must be a regulated 12 volts DC with a minimum input from the train control AC or DC power supply of 13.5 VAC connected to pos 3 and 4 of the rectifier bridge. The ground bus of the regulated 12 volts supply must be connected to the system ground. The independent speed reference voltage is taken directly from the train speed control module or can be taken by connecting directly from the tracks to positions 5 and 6 of the rectifier bridge .The output of this bridge will always be a positive speed voltage signal whichever direction the train is going.
The 555 timer is really a poor replacement for the LM566 as a VCO (Voltage controlled oscillator) although it is linear in function a negative voltage range is needed to activate the timer and produce the RPM to relate to the actual engine speed thus the op-amp is used to invert the track positive voltage.
The main power supply to the system must be a regulated 12 volts DC with a minimum input from the train control AC or DC power supply of 13.5 VAC connected to pos 3 and 4 of the rectifier bridge. The ground bus of the regulated 12 volts supply must be connected to the system ground. The independent speed reference voltage is taken directly from the train speed control module or can be taken by connecting directly from the tracks to positions 5 and 6 of the rectifier bridge .The output of this bridge will always be a positive speed voltage signal whichever direction the train is going.
The 555 timer is really a poor replacement for the LM566 as a VCO (Voltage controlled oscillator) although it is linear in function a negative voltage range is needed to activate the timer and produce the RPM to relate to the actual engine speed thus the op-amp is used to invert the track positive voltage.
