This circuit uses a JFET, which may be of the type BF244 or BF245 and a PNP bipolar that may be the BC558 or BC559. The circuit has a high gain with low intensity signals. Its consumption is very low and can power be sourced by supplies voltages from 9 to 20 V. The consumption is of 8 mA with an input impedance of 1M ohm and 5 k output. R6 acts as a gain control. Several changes were made to the original circuit in order to obtain better performance. If using power supply, it must have excellent filtration.
