General Power Understanding

ok, this is going to be a very rudimentary lesson on power.  but just want to help you understand and be aware of how much power you're drawing and using in a given situation. 

watt - describes how fast a circuit uses electricity

volt - basic unit of electrical pressure or EMF

amperes - basic unit of electrical current - flow of electrons

* courtesy of this dictionary

Standard US voltage is ~110.  

Most devices are measured in watts. 

Most outlets/circuits are measured in amperes or amps.  

Here's the formula --> amp = watt/volt

e.g. You have a 1000watt projector plugged into a US outlet that is measured to be 110v. You know the circuit you're plugged into is only 15A.  Will you be OK? 

1000watts/110v = 9.1A 

Yes, you will be ok.  but you could not plug two of these projectors into the same circuit or else you blow the fuse. 

Most wall circuits are 15-20A depending on when they were installed b/c older electrical work often only had 15A circuits/wiring installed. 

ok, but the big question is what does draw a lot of power?  here's a short list:

* projectors and lights (look at the bulb wattage)

* amplifiers - esp for the subwoofers.  at normal usage the actual power draw will be low but if you get a real thumping song then the amp is going to push more sound to the sub, which will require more power and the wattage/amperage will increase. 

* b/c these are in our environment - rice cookers or water boilers - basically anything that heats up something. 

* microwave, hot pans, etc...

* vacuum cleaners

***last note: something that may affect your power in international settings, is what Hz the current is alternating at 50/60.  in the US it's 60Hz.  Europe and Asia is 50Hz.  If you do not verify your equipment is running at the correct voltage or frequency, you could severely damage your equipment.  Yes, the equipment would run but it could also be burning out the wires internally.  ouch!