Tofte Ventures

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GregTech's First Circuits, Built Part by Part

GregTech is the Minecraft mod where nothing is simple. A circuit is made of parts, and each part is made of other parts. TerraFirmaGreg is a modpack built on GregTech and TerraFirmaCraft.

This is the very start of that line: the vacuum tube, which is the first ULV circuit, and the Basic Electronic Circuit, the first LV one. Build them part by part, then plan the whole tree under one.

Open in Tofte Simulators

How to play

Build one puts an unfinished item on a belt. Tap the parts in the order the assembly line wants them. A wrong part is refused, and counted. The tube line goes resin circuit board, steel bolt, copper wire, copper wire, glass tube, then pump the air out. The circuit line takes two vacuum tubes, and they have to be tubes you made on the tube line.

Plan the whole tree has a menu for every component under the circuit, listing every way the pack offers to make it. Change one and the totals below it change: copper and the other metals, sticky resin, glue, energy, machine time, crafts by hand, and anything left over.

Where the recipes come from

Every recipe here is read from the modpack's own files, and names the file and recipe id it came from. There are three sources, each at the version the pack pins:

All three are open source under the LGPL. Nothing is copied from their art: the drawings are plain shapes drawn here. I read the recipes, and did not run them in the game.

TerraFirmaGreg changes more than you might expect:

  • It removes GregTech's crafting-grid recipes for the vacuum tube, the LV circuit and the printed board.
  • It adds a Create assembly line for the tube and one for the circuit. These are the lines the game above plays.
  • It cuts the first printed boards by hand on an Artisan Table: a resin circuit board and 8 copper wires, with a screwdriver and wire cutters.
  • It swaps the steel bolt in GregTech's three tube assembler recipes for a resin circuit board.

There are 38 recipes in all. A script reads every one back out of the three source trees and checks its timing and power against the files.

"They'll get cheaper in a moment"

TerraFirmaGreg's own quest for the vacuum tube says:

Crafting Vacuum Tubes might make you question your existence. They're very expensive right now, but they'll get cheaper in a moment - that's the general GregTech philosophy!

Here is how much cheaper, in copper.

Six horizontal bars, one per step, showing ingots of copper in one Basic Electronic Circuit, each split into the copper in the board, the vacuum tubes and the resistors. By hand, on Create and the Artisan Table: 7 (board 4, tubes 2, resistors 1). Resistors from fine wire, still by hand: 6.25 (4, 2, 0.25). Board on the assembler, from foil: 3.25 (1, 2, 0.25). Tubes on the assembler, with red alloy: 1.92 (1, 0.667, 0.25). Circuit assembler, two circuits a board: 0.958 (0.5, 0.333, 0.125). Tubes from annealed copper: 0.875 (0.5, 0.25, 0.125). A note says that is 8 times less, and the biggest single drop is the board. Each bar changes one route from the bar above. Drawn from the engine's plans, in the long run with nothing left over.

By hand, one circuit takes 7 ingots of copper. Four of them go into the board, because the Artisan Table asks for 8 copper wires and a wire is half an ingot. Two go into the two vacuum tubes, at two wires each. One goes into the resistors.

Then each step takes some of it away:

  • Fine-wire resistors: 6.25. The resistor quest says to prefer the recipes that use fine wire, and the numbers agree. Two fine wires make two resistors, an eighth of an ingot each, against half an ingot each from single wire.
  • The board on the assembler: 3.25. Four copper foils, a wood plate and 100 mB of glue make one board. That is one ingot of copper instead of four, and the biggest single drop. The Artisan Table's four-at-once pattern does not help: it uses quadruple wire and still costs four ingots a board.
  • Tubes on the assembler: 1.92. With 18 mB of red alloy, the same glass tube, resin board and two wires make three tubes instead of one.
  • The circuit assembler: 0.958. It makes two circuits from one board, two resistors, two red alloy wires, two tubes and 144 mB of molten tin (or 72 mB of soldering alloy). That is only because the pack's config leaves GregTech's harderCircuitRecipes off; turned on, it makes one.
  • Annealed copper tubes: 0.875. Annealed wire makes four tubes a batch.

That last route is the least copper any combination of the four menus that matter reaches. The engine tries all 432 combinations to be sure. The planner's "Machines" preset, which uses the red alloy tubes and the plainer resistors, lands at 1.08.

Copper is not the only bill

The machines save copper and cost power. By hand, the only GregTech machine in the tree is the compressor pressing wood plates, so one circuit costs 1,600 EU. The machine route costs 5,527 EU a circuit, spread over the extractor, compressor, forming press, assembler and circuit assembler. These are base durations, before a higher-tier machine overclocks them.

By hand, one circuit is 14 crafts: 7 at the crafting grid, the Artisan Table and glassblowing, 4 wood plates on the compressor, and 3 runs of a Create line with 17 steps between them. On machines, two circuits take 12 crafts and leave one vacuum tube over.

The check

Every toy on this site carries the number that says whether to believe it. Here it is two ledgers:

  • The planner's books. For every item in every plan, what was made plus what came off the shelf has to equal what was used, plus what was left over, plus what was delivered. The tests run 1,600 plans on random route choices through that and require every book to close.
  • The source check. Every recipe row is read back out of the three source trees at their pinned versions. The duration and power of all 38 are checked against the files, and each file's recipe block is printed beside the row it became.

The tests also pin the 7 ingots by hand arithmetic from the recipes.

There is a smaller check too: the metal books agree with GregTech's own machines. A single wire holds half an ingot, and the wiremill makes two from one. A fine wire holds an eighth, and the wiremill makes four from a single wire. A foil holds a quarter, and the bender makes four from a plate. So on those machines the copper figures here are what the wires really cost.

What is and is not modelled

  • Metal parts (wires, foils, bolts, plates) come off a shelf, booked at the metal GregTech says they hold. TerraFirmaGreg also makes plates and wires by hand at an anvil, and those costs are not read here.
  • Sticky resin, wood dust, glass and paper come off the shelf too.
  • Create's lines run on rotational power, not EU, so their steps are counted and not timed.
  • Tools are listed, not worn down.
  • The ULV circuit tag also holds a NAND chip, which needs a system-on-chip and an MV circuit assembler. Two later electron tube recipes need a plastic circuit board. All three are left out.

The recipes and the planner live in our own engine, powered by rainshower, and the site's build check holds the numbers in this post to it.

It sits next to the other games: Little Rocket, Orbit Golf, and the physics playground.

Correction, 27 September 2026: GregTech's circuit assembler adds solder to every recipe that has none of its own: 144 mB of molten tin, plus a second copy of the recipe with 72 mB of soldering alloy. That happens in the recipe type's code, not in the recipe, and the first version of this post read only the recipe, so its circuit assembler was missing the solder. Neither solder holds copper, so every copper and energy figure above is unchanged. The planner now carries the solder in both versions, and the search counts 432 combinations, where it said 288. The source check now reads the recipe types' own additions too. The crystal chips post is where this turned up.