保护环

• If the node is at , or near to , ground then a grounded guard ring will be appropriate , if it is at some other potential it may be necessary to use a high input impedance buffer amplifier , with its input connected to the node , to force the guard ring to the node potential
  如果被保护的节点的电位是（或接近）零电位，采用地线保护环最为合适；如果节点电位是其他值，那么可以用高输入阻抗放大器组成缓冲器，输入端连接该节点，输出端连接保护环。