| 摘要 |
<p>The amplifier stage provides a rectangular signal across a load (L) which may be largely capacitive. It includes at least one amplifier mounted in bridge mode, in which a first pair of transistors (T1,T2) operate alternately in emitter-follower mode and a second pair of transistors (T3,T4) alternately closing the load circuit (L). The four transistors (T1-T4) of the bridge amplifier have their bases supplied by four current sources respectively (31-34) to ensure a maximum impedance for the load circuit for direct current. The second pair of transistors (T3,T4) are alternately connected in diode mode. To control the signal amplitude, a generator (12) provides a control voltage (VA) whose value consists of a fixed part and a variable part which corresponds to the required signal amplitude.</p> |
