This low noise circuit was obtained from a 1980s US RF publication. Transistors used are uncommon today and the gain is 19 dB..
This Hughes circuit is from 1968. Equivalent modern components can be used. The input impedance is...
This type of sensor was used in sensitive infrared systems from the 1960s. This circuit was found...
August 2016 –It can be purchased from Mouser Electronics the new converters BD7F100 and BD7F200...