Why won't the router turn on?

Question

network hardware

Hello!
Tell me why when I built up the cable for the router from the PSU (12v, 1.5A), by 25m +, the output voltage dropped (or current strength), because the router often does not turn on after turning off, and turns on 1 time out of 20-30, then it works for a long time, until the next. shutdowns. Rostelecom looked, they said that the router does not have enough voltage. They gave me another PSU, a new one (without build-up) or an old one without build-up - it works the first time. But the new one with a build-up does not work at all, even the indicators do not light up, but there is voltage, but, unfortunately, there is no voltmeter.
I understand that the resistance has increased, or is there some kind of loss due to the long distance?
PS When installing the cable, a critical error was made - an audio cable was used, i. section is smaller. Mb is this the case? But how is this explained?
PS I'm sorry for the stupid question.
Thank you.

Answer 1

Longer cable - more resistance - more voltage drop.
There are two options
1) Stretch 220V to the router
2) Take a PSU for a higher current, for example, a regular PSU for 12V 1A - take it for 3-5A, although it is better to resort to option 1

Answer 2

8th grade high school - ohm's law

Answer 3

Ответ очевиден, роутер не включается потому что был нарощен кабель. Судя по всему вы наростили хвост с уже выпрямленным - низким напряжением, а нужно было не курочить БП, а просто протянуть удлиннитель с 220 вольтами поближе к роутеру.
Как вы думаете, почему существуют линии электро передач на 110, 330 и 750 киловольт, и отчего зависит выбор напряжения в ЛЭП ?