The output voltage of a transformer in a microwave oven typically depends on the region and the power rating of the oven. In most household microwave ovens, the output voltage of the transformer can be around 2,000 to 3,000 volts.
The transformer in a microwave oven is responsible for converting the standard household voltage (usually 120 or 240 volts) to the high voltage required by the magnetron (the microwave-generating component) to produce microwaves for cooking food. The high voltage is necessary to excite the electrons in the magnetron and create the microwave radiation that heats the food.
Please note that attempting to modify or tamper with the internal components of a microwave oven can be extremely dangerous and is not recommended. Microwave ovens are designed with safety features to prevent accidental exposure to high voltage components. If you have any issues with your microwave oven, it's best to contact a qualified technician or the manufacturer for repair and service.