Gallery, Projects and General > How to's
How to Make a Power Supply
Bernd:
Darren,
Here's a quick run down of how the power gets into the house. 220v to outside meter. From meter to panel box. Panel box has the circuits for all the rooms. Power is run through a circuit breaker, usally 15 to 20 amps. Then the wire is run to the room plugs. No fuses in the plugs themselves, except for any outlet near water supply, usally kitchen and bathroom. These plugs have ground fault interupt circuits in them and will shut power off to the wall outlet.
Usally when somebody shows a diagram of a circuit they include a fuse and power light on the mains side of the transformer for saftey reasons. A majority of the applances do have an interanl fuse. Just today the microwave oven blew the internal fuse. It is a 15amp fuse. The power line it's connected to has a 20 amp circuit breaker. A dead short would probably open both fuse and breaker.
I don't know if all electrical appliances have internal fuses or not. Rather confusing, I know. :zap:
You won't want to look through the electrical code book, it's quite thick. :)
Probably hasn't helped any but you get the idea.
Bernd
Bernd:
Darren,
I've done a bit more research on published power supplies, but couldn't find some of my electronic books. I did a google search and came up with this PDF file. It's call Power Supply Design Basics.
I don't see any fuse, on/off switch or power on indicator on the mains line in their example. I still think it's good practice though.
Hope you don't mind me adding this to your thread.
Bernd
Darren:
Bernd I can't see that page for some reason, must be the US anti terrorist action coming into play, must think I need it to do some bad things :lol:
Generally if you need telling that you need a fuse in a mains circuit then you shouldn't be playing with this stuff anyway.
As a rule, people showing other people electronic circuits do not include the peripherals.
It would be a bit like me giving you a slap on the wrist for showing someone how to mill a chunk of metal and not mentioning that they need to wear safety glasses. :thumbup:
Bernd:
--- Quote from: Darren on May 18, 2009, 07:16:28 PM ---Bernd I can't see that page for some reason, must be the US anti terrorist action coming into play, must think I need it to do some bad things :lol:
--- End quote ---
Interesting. It's an app note on basic power supplys from the SGS-Thomson Microelectronics.
All right I'm giving up on this while I'm still somewhat sane. ::) Must have been to many of these :zap: when I was younger.
Bernd
Alan Haisley:
--- Quote from: Darren on May 18, 2009, 02:08:14 PM ---In the UK many electrical goods do not have an internal fuse.
This is because our wall socket plugs have internal fuses. This makes it quite hard to connect anything to the mains supply without a fuse.
--- End quote ---
Darren,
Does UK house wiring include fuses or circuit breakers at the service point in addition to the plug fuses? If not I'd worry about a broken wire short in the wall.
Alan
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