Strange Buzzing?

[JulianHaynes]

Remember that game called 'Operation' where you try to remove plastic organs but if you touch the sides the patient's nose lights up and buzzes? Well, our children have one and when it is not in use it is stored about half a metre from our electric cooker on the other side of a wall. Every time we turn off the cooker the Operation game buzzes! (The light doesn't come on though) It never happens when the cooker is switched on, when the Operation game's batteries are removed or when somebody touches the metal contacts. Also the game has to be in exactly the right position. I know I'm a sad old cookie but why is this?

[Sensei]

Have you ever noticed when you are using a vacuum cleaner that there are interference lines in the TV? I'll try not to bore you with the techno babble. Well, those interference lines are a result of current flowing on & off through a coil in in the motor. When current stops flowing through a coil, a huge voltage spike is produced- that spike is what you are seeing in the TV. The electric cooker also has a coil in it, when you shut it off, it also produces a voltage spike. I suspect that the part of the game that controls the buzzer is picking up that spike, just like a radio reciever. A good test would be to plug a TV into the same outlet and see if there is interference when you turn off the cooker.