Looking online I can see average dimensions of 6cm x 4cm x 2cm....

such as
https://cpc.farnell.com/elmdene/vrs121000eb/psu-cctv-12v-1a-uncapsulated/dp/SR08986
https://www.ebay.co.uk/itm/192124063283


Taking the physics into account of whats happening here(the AC to DC conversion), isit too much to ask to get a device much much smaller than the aforementioned dimensions?

The device the DC current has to power is a mobile router, rated at 12vdc 2.5amp

 

What is the reason you need a "tiny" power supply?
I would advise you to stay away from tiny power supplies like you show above. For one thing, I doubt an LED driver is the sort of supply you need, and the electrical insulation in most of those cheap power supplies leaves a lot to be desired. Some are quite dangerous.
Those from Farnell you could trust.
But, all that you show (the first would not open, due to site maintenance) are way too small in power for what you asked for.
Don't confuse "3W" with "3A".
12Volts * 2.5Amps = 30Watts.
For reliability, do not skimp on your power supply. Maybe look for a 40W or 50W version.

 

You need a 2.5A one for the router, like this one.

https://cpc.farnell.com/elmdene/vrs...-3-5a-uncapsulated/dp/SR08988?st=12v psu cctv

 

The one you linked is only 3W. You need 30W. Higher power ones will be larger.

Bob

 

maybe consider another router. for those who like to travel lite, there are nano routers which are tiny and consume much less power.

 

Taking the physics into account of whats happening here(the AC to DC conversion), isit too much to ask to get a device much much smaller than the aforementioned dimensions?

Yes it is.
More power requires more volume.
That's the physics.

 

What is the reason you need a "tiny" power supply?
I would advise you to stay away from tiny power supplies like you show above. For one thing, I doubt an LED driver is the sort of supply you need, and the electrical insulation in most of those cheap power supplies leaves a lot to be desired. Some are quite dangerous.
Those from Farnell you could trust.
But, all that you show (the first would not open, due to site maintenance) are way too small in power for what you asked for.
Don't confuse "3W" with "3A".
12Volts * 2.5Amps = 30Watts.
For reliability, do not skimp on your power supply. Maybe look for a 40W or 50W version.

Need small for a compact project I am working on.

maybe consider another router. for those who like to travel lite, there are nano routers which are tiny and consume much less power.

Good idea, but still needs ac to dc conversion

Yes it is.
More power requires more volume.
That's the physics.

Understood, however, I am wondering are there multiple ways to skin a cat, and do some of the other ways of converting AC to DC use less material(but could be more expensive for example?)

 

What about something like this guys?

https://www.flyingtech.co.uk/electronics/mini-2-6s-5v-3a-12v-2a-step-down-voltage-regulator

It seems very small - It can output up 3A at 5V and 2A at 12V.

I understand my router needs 2.5amp, but lets say they did another version of this which outputs 2.5A at 12V, would it be suitable?
Its really small...

 

It seems very small - It can output up 3A at 5V and 2A at 12V.

That is just a step down reg from maybe a 19V laptop supply to the required 5 or 12V. Not mains input.

As it sound like your device will be plugged in, why cannot you use a plug pack?