A new general realization theory of FET-like voltage-controlled negative differential resistance device is presented. A feedback-transfer model (VIM) of the FET, which contains four different kinds of feedback connections and their own mathematical conditions, is set up. Based on this model, a general simple realization technique is explored. Using this technique many negative differential resistance FET-like integrated devices either new or published are generated, and their integrated circuit configurations and basic properties are studied and discussed. Application example for a specific device is demonstrated, which substantiates the exactness of the proposed theory.