| 摘要 |
<p>The active coupling circuit joints two stages (T1,T4) of a solid state amplifier in series. The proposed arrangement is specifically intended for use in the manufacture of integrated circuit amplifiers, and serves to reduce the surface area required for the coupling capacitor (C). The coupling capacitor (C) is connected between the input and gate terminals of a FET (T2). The gate is also connected to the output terminal through a high value resistor (R3), typically of the order of 100 megohms. The FET output forms the input to the second stage amplifier (T4). It is desirable to connect a further transistor (T3) to the second stage gate. This transistor has output and gate connected to the negative supply. The arrangement allows the use of a coupling capacitor several times smaller than normal, and thus eases manufacture on an integrated circuit chip. The geometry of the resistor (R3) and connections is arranged to give a high value of parasitic resistance (R2,R4) to earth.</p> |
