Build Filters Without PC Boards

摘要

When stand alone passive components are not readily available as standard off the shelf commercial units, lab-built engineering models are often the best solution. At other times, passive circuits may be critically needed as test accessories when unanticipated problems arise during final subsystem and system testing. In these situations, time constraints can be met with prototype units that can be designed, assembled, and tested in only a few hours, as long as printed circuit boards (PC boards) are not used. This types of component construction is readily accomplished at low power levels with frequencies below 100 MHz. At VHF, passive circuits such as bandpass filters can be readily implemented using standard die cast aluminum boxes as housings. Coaxial connectors and some of the circuit elements are screw assembled to the housing. Other circuit elements are assembled using soldered connections inside the housing.