Store the electrical energy needed by a microwaves high-voltage heating system with this replacement capacitor. During cooking, the capacitor works with the transformer, diode, and magnetron to help create the energy that heats food. A faulty capacitor may be linked to no heat, loud buzzing, or a fuse that blows when cooking begins. Howev...Read moreer, these signs can also come from other high-voltage components, so proper testing is important. Microwave capacitors may hold a deadly electrical charge even after the power cord is unplugged. For this reason, testing and installation must be completed by a qualified appliance service technician.