How does this work?

While cleaning out my closet at my parents house, I found this bizarre contraption. I wasn't sure what it was supposed to do at first, but I plugged it into my phone and the phone line (lol) and it started charging. I think I made it to get power in abandoned buildings with the power shut off. I have a horrible memory, and I've blocked out middle school almost entirely. I could research how landlines work in depth and then work out how that relates to this circuit, but I thought it might be more time efficient for me and fun for the community to crowd source it here. It seems obvious to me that landlines must have some sort of oscillating/alternating current (perhaps of the order of kilohertz) because of the long distances involved, the audial nature of the dial tone, and the diode in this circuit. What I don't know >How does it charge without the 4 diodes of a typical full wave rectifier? >What does the transistor do? >How much power can it provide? >Is the output different from a normal charger, and if so, could it damage electronics? >How would a call affect charging? Any advice for a hypothetical person seriously considering pursuing a recently reawakened childhood dream of blanketing their city in a pirate radio mesh? (It seems to me that this would make triangulation MUCH harder.)

>It seems obvious to me that landlines must have some sort of oscillating/alternating current (perhaps of the order of kilohertz) because of the long distances involved, the audial nature of the dial tone, and the diode in this circuit. Yes, in fact landlines carry waveforms pretty much exactly the same as the audio you hear. They're not very strong. >How much power can it provide? I'm surprised it can supply any power at all, since you shorted ground and neutral.

>>8114 OH never mind that's not ground, it's just greenish so I assumed.

The single diode works as a half-wave rectifier, it uses only the top part of the AC waveform. And it doesn't make sense for that to be a transistor. Its probably a 5V voltage regulator (for example 7805)

>>8113 See: >https://www.instructables.com/How-to-Get-Emergency-Power-from-a-Phone-Line/ >How does it charge without the 4 diodes of a typical full wave rectifier? Phone line power is DC when idle, the diode is only there for protection in case the phone starts ringing. >What does the transistor do? As anon above already said, it's an L7805 IC, it brings the voltage down to 5V and dissipates the rest as heat. >How much power can it provide? Not much, the article mentions ~60mA. Phone chargers these days are rated for 2.1A or more. But it should be enough to charge your phone as long as you're not actively using it. >could it damage electronics? Only if it blows up and the full line voltage shoots through. Which it probably won't, given the low current. >How would a call affect charging? It shouldn't affect the charger, but the line phone might have a problem with its supply voltage dropping.

How is this sort of LARP supposed to work? 1) Phone line terminates at PON modem which converts it into VOIP and transmitted over optical wire to ISP. 2) PON router is obviously powered by AC electricity, with very low probability of it having a backup battery despite many of them having dedicated battery sockets. 3) If there is no electric power on your block, there is no current in phone line.

>>8138 it's obviously meant for oldschool landlines. Telephone companies are required to keep huge backup batteries to power them in the event of a power outage. My landline at home used to work even when the power was out, although it's very hard to find a phone these days that will work without being plugged in to a wall socket.

>>8139 Well, what a bummer. In my city all phone companies scrapped copper wires and laid optics everywhere around 2013. Each "landline" household phone essentially becomes pic related with a VOIP terminal inside PON modem/router. Cell network at this moment is more reliable means of communication since power outage in a building is more likely to happen than power outage in whole neighborhood where cellular masts are. Unless you really do have a backup battery for the router which you most likely do not, and cell phones do.

>>8163 which country committed such elegant telecommunication suicide by getting rid of reliable copper?

>>8167 Not sure where anon lives, but I suppose he lives in a fuarrrked up country where people steal copper wires. Same happened here. fuarrrking crackheads...

>>8167 >>8256 There's not enough copper in phone lines to even make them worth scrapping. This must have been done for some other reason.

Electrical engineering bachelor here Thats a diode with linear voltage regulator, there must be a capacitor somewhere to smoothen out the rectified half-wave of AC, but basically AC is made to half of the wave and then capacitor smooths the half wave into somewhat of a straight line, linear voltage regulator probably is set up to either be default 5v or by side resistors to output 5v seeing how there is an USB nearby I assumed 5v. The capacitance through its transitory state of "being a pool of electrons" dampens the fluctuance in flow of electrons, lets say it that way. And diode allows electrons only to go through one direction because of PN barrier that allows electrons to jump into "holes" of doped silicon with missing electron crystalline structure of P side but not N (sulfur is P, nutrogen is N if I remember clearly) Thats about it. LVO can be explained, but its a bit more complex, a lot of soykaf like op amps, current sinks and current mirrors. Cant really be explained in a post like this one

>>8315 In an apartment building with 200-300 flats (equal number of lines going straight to local district switching station) and very competitive ISP market of 5+ ISPs in each such building with faster speeds, e.g. offers of 150M download speed DOCSIS on top of existing cable TV wiring and even symmetric speed 100M Ethernet LANs cum local ISPs with FTTB, your average state-run telephone company with their wimpy overpriced ADSL quickly realizes that it's time to scrap all copper and invest into GPON infrastructure. Too bad, it's a clustermess of proprietary hardware where end user pays for lease of a terminal box and also for electricity powering it without actually having arbitrary control over what this hardware is really doing.

>>8315 If people are desperate enough, you'd be surprised.