Signal voltages amplification by pre-amplifier

摘要

The pre-amplifier uses an operational amplifier (2) configured as a voltage follower circuit, with its signal input (3) receiving the signal voltage from a high impedance signal source (1). There are parasitic capacities between the signal input (3) and the two voltage supply terminals (4,5). The influence of these parasitic capacities on the signal voltages is however much reduced by the fact the first and the second supply voltages can be shifted parallel to one another, depending on the output signal of the pre-amplifier on the signal output (8). The output signal then serves directly as a reference potential for the voltage supplies (9,10).