Step 7: Common Configuration
By far the configuration that I see the most is the "Common" configuration (fig. 1). I call it common configuration because each coil has one end free and the other connected to a common wire (to which all other coils are connected too).
This configuration is by far the easiest configuration to use. No extra work is required, all we need to do is work out which wire is which.
There will be one wire that upon closer inspection is many wires soldered together. This is the centre tap. Pick any other two wires. You now have your two "ends". In figure two we are simply ignoring the "red" coil, you may ignore more or none - the number of coils on a "common" configuration varies, I have seen two and three coils, but I see no reason why there couldn't be more.
That's all that you need to do for this step, so keeping track of which wire is which, jump to the "Time To Test" step.