oui...c'est bien ça dont il s'agit...désolé, c'est en anglais
High power transformer found in a microwave oven that steps up wall voltage to around 2 kVAC, at power usually between 900 W and 1700 W. Be careful- these are not current limited! They are often known by the acronym MOT.
This is a non-ideal transformer whose purpose is to generate typically 1 kW of pulsed 5 kV DC into a magnetron, by driving a half-wave doubler.
The turns ratio is designed to give about 2 kV AC to the main sedcondary winding, one end of which is bonded to the grounded core. An additional secondary provides an isolated supply of typically 3 V at 15 A for the magnetron heater.
As it is intended to drive a capacitive load, the leakage inductance of the tranformer is deliberately increased by adding a small magnetic shunt between the primary and secondary coils. The inductance is roughly equal and opposite to the doubler capacitance, and so reduces the output impedance of the doubler. This specified leakage inductance classifies the transformer as non-ideal.
The transformer is designed to be as cheap to manufacture as possible, with no regard for efficiency. This is because it is the manufacturer who pays for the copper and iron, but the user who pays for the energy consumed. Thus the iron area is minimised which results in the core being taken well into saturation with result high core losses. The copper area is also minimised, resulting in high copper losses. The heat that these generate is handled by forced air cooling, usually by the same fan that is required to cool the magnetron. The core saturation is not part of the non-ideal classification, it is merely as a result of the economics of manufacture.
Note that powering a Microwave Oven Transformer outside the original oven carries the risk of injury or death due to electrical shock. This should not be attempted unless you have enough knowledge of electricity to understand the risk and take the relevant safety precautions.