Hello there, I am trying to get my head around the 'track circuit calculations' and in particular I have been looking at 'TC calc 1995 Q1.' I just wanted to know how the ballast resistance of 3.75 Ohms was achieved depicted on the diagram of the simplified circuit, it does show an equation but I can't quite make it out if someone could shed some light on this it would be much appreciated.
Many thanks
Archie
Many thanks
Archie