FJV3107R is a NPN type transistor produced by Fairchild Semiconductor Corporation. Its typical characteristics are shown in Figure 1. The working temperature of the transistor is -55 ~ 150 °C, the maximum collector voltage is 50V, the collector-emitter reverse breakdown voltage is 50V, the collector-emitter saturation voltage is 0.3V, the output capacitance is 3.7pF, and the frequency gain bandwidth product is 250MHz.