| 摘要 |
An amplifier system having an input active device at its first input and having its second input provided through an inverting means to that first input. Such a system is of particular value for hearing aids, and in particular for hearing aid circuits which also require the ability to use as a selective input a "telephone coil" inductive sensor for ease of telephone use by the wearer, which coil requires to be switched in and out of the operative circuit. |
