Why can most household appliances run off AC but things like phones and computers require DC?

Question

Just wondering cus like wouldn’t it be more convenient to just plug your phone into the wall without a brick, or like cheaper to build a pc without a power supply? why do these devices need DC but lamps, fridges, fans, most household appliances can run off AC?

In: Other

Answer 1

TLDR: You have to use AC for power transmission, you have to use DC for electronics otherwise your electronics would work like shit.

AC is great at two things (probably more but whatever) switching voltage between really high and really low (really high for running power around the country, really low for running your water heater) and for making things spin. To make something spin you have to sort of push things around in a circle so you have to kinda push and pull in certain ways just imagine how your hand has to change direction all the time if you want to spin a wheel around.

AC is a spinny push and pull. DC is a constant push.

Electronics like your phone don’t spin, they just need a constant push to get their energy. But our power system and most “old” things spin to do something useful. The things that don’t spin were designed to use the spinny power because that’s what came into the house.

Because AC is so good at making power strong when pushing it out across the country, we need to start with AC. When it gets to your house it is great for running the spinny things, but for the pushy things there needs to be a brick to turn the spinny power into the pushy power.

Making the spinny power into pushy power results in energy loss, so there’s no reason to make devices like your toaster run on pushy power because then you’d have a toaster that makes heat out of pushy power and also a brick that makes heat out of spinny power sitting on your counter next to the toaster.

We could design electronics to work directly off of AC, but it would be like designing a car that required you to keeping smashing the gas pedal and releasing it at a specific rate to keep you going forward. Think how you would push someone on a swing, you gotta push, then relax for a bit, then hit them again at just the right moment.