Sometimes called MOSFET tetrodes, dual-gate MOSFETs were once very common in Ham radio designs. Doug DeMaw, W1FB, based many of his VFO and mixer designs on them, as did several other well-known authors. With large-scale integration, their use in industry has declined, and there are now no through-hole versions available on the market. There are, though, some surface-mount devices still produced, but understandably amateurs are reluctant to use them. These little half-inch breakout-boards might make experiments and home brewing with dual-gates a bit easier.

The breakout boards come with the MOSFETs pre-installed. You can add wires or leads as you desire. They would work particularly well for “Manhattan”-style construction. Currently, BF998 and BF2040 types are available. If stocks of other types are located, they will be made available as well.