When JFET is used as a low-noise and high-operational amplifier in input tube, plate fond and back grid can be separated to decrease input bias and increase input impedance.

• 在JFET作输入管的低噪声高精度运放中,为了进一步减小输入偏流,增大输入阻抗,可使顶、背栅分离,且仅以顶栅接输入信号,而背栅接片内控制电路。