On the correct choice of transformer ratio in low noise preamplifiers for large detector capacitances

In the design of transformer coupled preamplifier for large detector capacitances the transformer ratio is customarily made equal to the value which meets the capacitive matching condition. If, however, parallel noise as well as series noise external to the amplifying device are present, the optimum choice of the transformer ratio may differ substantially from the previous one. The paper aims at investigating the optimum transformer ratio with a quite general configuration of noise sources, yet sticking to the model of ideal transformer. (orig.)