More manual

Sections on rubber and electrical power.

manual.md

@@ -242,6 +242,10 @@ more than one of the input item: the quantity required is part of
 the recipe.  Centrifuging is only performed by a single machine type,
 the MV (electrically-powered) centrifuge.
 
+Currently, centrifuging recipes don't appear in the unified_inventory
+craft guide, because unified_inventory can't yet handle recipes with
+multiple outputs.
+
 Generally, centrifuging separates the input item into constituent
 substances, but it can only work when the input is reasonably fluid,
 and in marginal cases it is quite destructive to item structure.
@@ -422,15 +426,107 @@ There's one more iron alloy in the game: stainless steel.  It is managed
 in a completely regular manner, created by alloying carbon steel with
 chromium.
 
+rubber
+------
+
+Rubber is a biologically-derived material that has industrial uses due
+to its electrical resistivity and its impermeability.  In technic, it
+is used in a few recipes, and it must be acquired by tapping rubber trees.
+
+If you have the moretrees mod installed, the rubber trees you need
+are those defined by that mod.  If not, technic supplies a copy of the
+moretrees rubber tree.
+
+Extracting rubber requires a specific tool, a tree tap.  Using the tree
+tap (by left-clicking) on a rubber tree trunk block extracts a lump of
+raw latex from the trunk.  Each trunk block can be repeatedly tapped for
+latex, at intervals of several minutes; its appearance changes to show
+whether it is currently ripe for tapping.  Each tree has several trunk
+blocks, so several latex lumps can be extracted from a tree in one visit.
+
+Raw latex isn't used directly.  It must be vulcanized to produce finished
+rubber.  This can be performed by simply cooking the latex, with each
+latex lump producing one lump of rubber.  If you have an extractor,
+however, the latex is better processed there: each latex lump will
+produce three lumps of rubber.
+
+electrical power
+----------------
+
+Most machines in technic are electrically powered.  To operate them it is
+necessary to construct an electrical power network.  The network links
+together power generators and power-consuming machines, connecting them
+using power cables.
+
+There are three tiers of electrical networking: low voltage (LV),
+medium voltage (MV), and high voltage (HV).  Each network must operate
+at a single voltage, and most electrical items are specific to a single
+voltage.  Generally, the machines of higher tiers are more powerful,
+but consume more energy and are more expensive to build, than machines
+of lower tiers.  It is normal to build networks of all three tiers,
+in ascending order as one progresses through the game, but it is not
+strictly necessary to do this.  Building HV equipment requires some parts
+that can only be manufactured using electrical machines, either LV or MV,
+so it is not possible to build an HV network first, but it is possible
+to skip either LV or MV on the way to HV.
+
+Each voltage has its own cable type, with distinctive insulation.  Cable
+segments connect to each other and to compatible machines automatically.
+Incompatible electrical items don't connect.  All non-cable electrical
+items must be connected via cable: they don't connect directly to each
+other.  Most electrical items can connect to cables in any direction,
+but there are a couple of important exceptions noted below.
+
+To be useful, an electrical network must connect at least one power
+generator to at least one power-consuming machine.  In addition to these
+items, the network must have a "switching station" in order to operate:
+no energy will flow without one.  Unlike most electrical items, the
+switching station is not voltage-specific: the same item will manage
+a network of any tier.  However, also unlike most electrical items,
+it is picky about the direction in which it is connected to the cable:
+the cable must be directly below the switching station.  Due to a bug,
+the switching station will visually appear to connect to cables on other
+sides, but those connections don't do anything.
+
+Hovering over a network's switching station will show the aggregate energy
+supply and demand, which is useful for troubleshooting.  Electrical energy
+is measured in "EU", and power (energy flow) in EU per second (EU/s).
+Energy is shifted around a network instantaneously once per second.
+
+In a simple network with only generators and consumers, if total
+demand exceeds total supply then no energy will flow, the machines
+will do nothing, and the generators' output will be lost.  To handle
+this situation, it is recommended to add a battery box to the network.
+A battery box will store generated energy, and when enough has been
+stored to run the consumers for one second it will deliver it to the
+consumers, letting them run part-time.  It also stores spare energy
+when supply exceeds demand, to let consumers run full-time when their
+demand occasionally peaks above the supply.  More battery boxes can
+be added to cope with larger periods of mismatched supply and demand,
+such as those resulting from using solar generators (which only produce
+energy in the daytime).
+
+When there are electrical networks of multiple tiers, it can be appealing
+to generate energy on one tier and transfer it to another.  The most
+direct way to do this is with the "supply converter", which can be
+directly wired into two networks.  It is another tier-independent item,
+and also particular about the direction of cable connections: it must
+have the cable of one network directly above, and the cable of another
+network directly below.  The supply converter demands 10000 EU/s from
+the network above, and when this network gives it power it supplies 9000
+EU/s to the network below.  Thus it is only 90% efficient, unlike most of
+the electrical system which is 100% efficient in moving energy around.
+To transfer more than 10000 EU/s between networks, connect multiple
+supply converters in parallel.
+
 subjects missing from this manual
 ---------------------------------
 
 This manual needs to be extended with sections on:
 
-*   rubber
+*   the miscellaneous powered machine types
-*   electrical networks
-*   the powered machine types
 *   how machines interact with tubes
+*   the generator types
 *   the mining tools
 *   radioactivity
 *   frames