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How far can you run 12 AWG wire with 20 amps?
Typically you don't want more than a 10% drop in voltage. If it were a 120 VAC circuit that would be a drop of 12 volts. At 20 Amps that is a resistance of .6 ohms. That is about 380 feet. Allowing for a 10% drop in voltage would allow you to run 20 amps on 12 gauge copper to 151 feet. Also, the NEC suggests, but does not require, that voltage drop be limited to 3% on branch circuits. In the field this is treated by most electricians as an absolute requirement, not a suggestion. This allows you to run a 20 amp load to only 45 feet on 12 gauge wire. Notice that voltage drop is calculated based on connected load, not the rating of the circuit. A 20 amp load would be connected to a 25 amp or 30 amp circuit, requiring larger wire and allowing for longer distance. In a home a 30 amp circuit would most likely be 240v and would require #10 gauge conductors. Using these numbers to calculate a 3% voltage drop allows you to run this circuit 145 feet. At 120v on #10 gauge wire a 20 amp load can be run just over 72 feet.
What is the current in a lamp if 72 coulombs pass through it in 24 seconds?
72 coulombs in 24 seconds is 3 amperes.One ampere is one coulomb per second.
Why you use class AB push pull power amplifier?
high efficiency nearly with my practical 72%..and the cross over distortion had been eleminated by the slight shift of q point above cut off region Class AB push pull is used in battery powered amplifiers as used in radios because the current drawn reduces during quiet periods, saving battery power.
Why does China produce so many electrical items?
China is a huge producer of a lot of items about 72% of everything you flip over and look at the bottom will say, 'Made in China' its not just electrical, but maybe it is because in u.s.a. a lot of people use electronics and we evolve around electronics, we depend on electronics, and if we are getting shipments from China possibly they want to make the most profit from us so the make electronics, and so when it ships they get more stuff, but i also have always wondered why everything was released in china first? xbox 360, ps3, Wii, etc...??
What is fault mva rating of circuit breaker?
Pre 1970 (72?) breakers were specified with a MVA assymmetrical interrupting rating. Breakers are now spec'd with a symmetrical rating, which is provided in amps or kA. There is an ANSI standard that provides conversion from assymetrical to symmetrical and vice versa. Converting from Asym. to symmetrical involves analyzing the open close interval, time between successive openings, breaker operating speed, breaker operating voltage, and whether the breaker is connected to a generator bus or not (usually has an unusually high X/R ratio which results in more DC offset). So...it is the interrupting rating, or how much (short circuit) power the breaker can interrupt. The faster the breaker operates, the higher the voltage, the closer it is to a generator, and the more times it is expected to open results in a lower interrupting amperage capability. If it is used beyond this rating, it is likely to internally fault when attempting to open.
