It is required to power it with energy, which can be connected using Aluminum Wire.
- Ensure that the circuit fabricator is powered. Either a battery can be used in the lower-left slot or power can be fed in (e.g. from the Coal Generator) from the left side of the block.
- A diamond has to be placed in the top left slot.
- Redstone dust must be placed in the slot with the redstone icon.
- Silicon needs to be placed in the center two slots. (From Galacticraft 3.0.10, other mods' silicon can also be used here, if set in Galacticraft's config.)
- The top-right slot determines what the output is. For example, if a Redstone Repeater is placed in there, an Advanced Wafer is produced.
- Bottom-right slot is the output. In this example, the Advanced Wafer will appear in that slot.
For greater efficiency, in Galacticraft 4 if you build your Circuit Fabricator in a zero-gravity dimension, it will create extra wafers from the same inputs (5 Basic Wafers or 2 Advanced Wafers). Galacticraft 3 you can have the same efficiency if you enable Quick Mode (note: Quick Mode has no effect on the Circuit Fabricator in Galacticraft 4: in Galacticraft 4, you must put the machine in zero gravity for this effect).
In Galacticraft 3 and Galacticraft 4], the Circuit Fabricator can be filled from a Hopper or by piping in items using pipes from another mod - the Hopper or item pipes (including Applied Energistics II) can be connected on the top or any of the 4 sides of the Circuit Fabricator, but not the bottom. The Circuit Fabricator will automatically place incoming Hoppered or piped items into the correct slots, and silicon will spread evenly between the two silicon slots (isn't that smart?)
Items made by the Circuit Fabricator can be extracted by a Hopper or item pipe on the bottom - just like a vanilla Furnace.