I have stumbled onto this article and also have a rat somewhere. I thought of using a car coil to exterminate them. In the past I built a circuit (kit) called a pet trainer. It works like a flip flop but pushes out 12v pulses. This is then connected to a 12v car coil and you put up a wire where you do not want the dog to go and the other to earth. When the dog touches the wire it gets a good jolt and quickly learns to stay out of certain areas. I was wondering if this would kill rats. The question is two fold. Firstly the circuit produces pulses which means the rat will have to make contact with both + and - to be electrocuted although the circuit pulses reasonable quick (not sure of exact timing. The other is, is the current strong enough to kill a rat if it only jolts a dog. Any comments please.