Wiki is out of date. But you can learn many things about the game if you read the json files, they are under the \data\json directory.
Here is the water purifier recipe from the recipe_electronics.json file:
{
"type" : "recipe",
"result": "water_purifier",
"category": "CC_ELECTRONIC",
"subcategory": "CSC_ELECTRONIC_TOOLS",
"skill_used": "mechanics",
"skills_required": [ "electronics", 1 ],
"difficulty": 3,
"time": 25000,
"reversible": true,
"decomp_learn": 2,
"autolearn": false,
"book_learn": [[ "advanced_electronics", 3 ] , [ "manual_electronics", 2 ]],
"qualities" : [
{"id":"SCREW","level":1,"amount":1}
], "components": [
[
[ "element", 8 ]
],
[
[ "bottle_glass", 2 ],
[ "bottle_plastic", 5 ],
[ "bottle_plastic_small", 10 ]
],
[
[ "hose", 1 ]
],
[
[ "scrap", 3 ]
],
[
[ "cable", 5 ]
]
]
}
As you can see, there are two rows:
"autolearn": false,
"book_learn": [[ "advanced_electronics", 3 ] , [ "manual_electronics", 2 ]],
So you have to learn it from that books.
In the books.json file you can see the in-game name of that books:
advanced_electronics ->Advanced Electronics
manual_electronics -> What’s a Transistor?