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1

If we have a phone with all of human knowledge, then I’m surprised that nobody has suggested searching the Internet archives on the phone for the Reddit topic where this question was asked and the answers given.


0

Since the device has all human info, I'm assuming that it is advanced enough to have inductive charging. Inductive/wireless charging would be safer than using a USB connection and is simple to build from wires. Combine that with the battery ideas and you could charge a phone until enough wire and other basic materials could be acquired to build a small hydro-...


2

Any battery in a phone removable or not is a module with it's own protection circuits which will cut it off when the voltage/current/temperature is out of range. So it is safe to charge/short circuit the battery directly. The battery's voltage range is like 3.0-4.3V which is wider than the phone input port range which is like 4.75-5.25V so it is easier to ...


7

A lot of these answers are forgetting something very important. The phone contains all of human knowledge. Assuming you are transported back with a full battery, look up and write down everything you can on electrical engineering in the time the phone is still running. Once you have written down all of the necessary information, get to work in building ...


26

Don't try to charge the battery inside the phone. Build a 10 cell lemon battery with copper and lead electrodes, which produces ~4.35V with a maximum current of about 1~5mA. Remove the battery from the phone and connect it to your lemon battery with the correct polarity (copper electrode is positive). At this low current there is no risk of damaging ...


5

Depends on the phone. If you give an LG G7 One 5 volts, it will happily charge away at whatever current it can reasonably pull. As other answers state, coming up with 5 volts (ish) is certainly doable, and the internal resistance of a battery from that timeline will take care of any over-voltage you accidentally create from impurities. If you give a ...


10

You could build a dynamo. One of the simplest designs for a dynamo is the homopolar generator, also known as a Faraday Disc. You'll basically need a: magnet copper disk commutator brush Line enough of them up and you should be able to produce the necessary voltage and current. With a skilled jeweler, you could then create gold wires to hook up to the +V ...


9

You've picked a very difficult thing to do. Besides the electrical problems, you also have the mechanical problems of making the connector. USB micro connectors are very precisely made, and you are going to have to connect wires to some very fine pins. I think what you want is beyond what you could reasonably accomplish. I mean you've got like two days ...


40

You could emulate Volta's pile if you could find some zinc and copper metal, and some acid, however the purity of such items might be pretty questionable. Which means you might get more voltage than you expected and damage the phone, with no possibility of repair. The cells Volta made produced about 1.1V so 5 of them would be about right (perhaps a bit high)....


13

It is possible to make a battery using electrolytes from vinegar, apples, etc. Depending on the type used you can get different voltages. If they do not match 5 V, put them in a series or parallel combination to get close enough to 5 V. A side issue is to create a Volt meter to measure voltage output (you don't want to damage your mobile phone having a too ...


2

What mattered was how much gold/silver the coins had. There are techniques to measure that but I can't remember exactly what these techniques were right now. It a coin had less precious metals then the other it would be worth less. So they measured the precious metal amount.


7

The metal value of gold and silver was the basis of their value, so if you didn't know the coin, you would simply weigh it on a scale. If you knew and trusted the coin, you might accept it at its known value. There were, however, numerous ways to cheat. One was to clip or shave coins by cutting small pieces off the edge of generally accepted coins and later ...


2

The relative weights of the coins would have been known so 7 florins = 13 crowns or whatever. If the coins were not recognised they would not have been accepted. The coins themselves with the official stamp would have provided a degree of surety that the coin was in fact made of gold. It would have been difficult to insert anything into a thin coin using the ...


2

While there have been several good answers about economics, one thing which puzzled me was the desire to have a "hot" war going for decades. Historically, very long periods of warfare, like the 100 years war, the 30 years war, the Seven Years War, the Napoleonic wars and the Cold War were generally short periods of intense combat interspersed with longer ...


10

I'm going to branch off of what Puppetsock posted and get a bit more theoretical. While he's absolutely correct that economic expansion in the conditions of the first world war is extremely unlikely, you could get more 'alternate history' and make those conditions more agreeable. The main issue that made WW1 so bloody was that military leadership hadn't ...


3

Let's think about this: Facts: 1. The cold war was indeed a war of (economic) attrition. (The west won as it happens - the other blokes got outspent.) So did either of the two sides have a second industrial revolution during the cold war period? 2. Yes, in fact that is literally exactly what happened. The "computer and space age" is the only thing ever ...


3

Not absolutely impossible. But very unlikely. WWI consumed men at a drastic rate, averaging about 50,000 military deaths per week for the whole war, and a similar number of civilian deaths. Those who were not killed were under huge pressure to join up and get involved in the fight. So generally, any potentially productive individuals were siphoned off for ...


1

When an intensive war is fought, it will put a significant burden on the economies of all the parties involved. That is unless the war is merely used as a stimulus by the parties involved, and not fought with a goal of conquest but with a goal to ensure it's perpetuity. The novel Nineteen Eight Four discusses a similar theme where there is a perpetual war ...


0

Have a quintumvirate, instead of a triumvirate. The odd number avoids deadlocks over minor issues. It is harder to keep an alliance of four backstabby partners together long enough to dispose of a fifth power, than to keep an alliance of two together long enough to dispose of a third. How can I prevent semi-independent royal families from rebelling ...


0

Power triangles tend to work so long as there is specialisation. If many people are competing over the same role, then the outcome gravitates towards only one winner. Consider instead that power should be shared amongst people with different primary responsibilities. As has been mentioned, this could be the likes of America's division between Executive, ...


0

Rome isn't a good example to examine the stability of triunvirates because by the time the romans tried this system the Republic was alredy doomed and the system was a hack to try to shore up the system and the hack failed. To have a stable triunvirate you need that the three rulers have equivalent powers and make it very hard for one to take the other's ...


2

Well, the original trimvirate was actually pretty stable. Crassus, Caesar, and Pompey were all populists, and they were united against the aristocratic faction. The instability came from Caesar and Pompey improving their profile with their military victories, which is why Crassus was so desperate to gain a victory in Syria that he got himself killed. Had he ...


-2

All tanks have manual back up systems. Electronics is not critical. Furthermore, an Abrams will run on anything that burns. As long as the technology is available for a wood or coal engine then the drive train is crappy but replaceable. Cannons are also replaceable. The real hold back is that there would be no reason. A horse drawn Cannon takes far less ...


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