We have reported the large-scale assembly of type-switchable field effect transistors (FETs) based on carbon nanotubes (CNTs) and nanoparticles (NPs). In this device, the charges stored in NPs adjacent to ambipolar CNT channels were adjusted to control the carrier type and density in the channels. We demonstrated the real-time reconfiguration of individual FET types and logic circuit functionality. Theoretical simulation of a model system was provided to explain this doping effect. This work takes advantage of the ambipolar properties of CNTs and opens up the possibility to build new types of devices with reconfigurable functionalities.