e)How much AC voltage is required to produce a current of 20mA through the body? ( show your calculations)?
487275
Further reading of the reference given in answer 3 motivates this WARNING:\nA given AC current has greater biological/neurological effects than DC. 15 ma is enough to cause "Shock--painful, severe effects: muscular contractions, breathing difficulty". Also,"The threshold for a painful shock, in which muscles cannot let go, is 10.5 mA for AC current."\nJust in case this information inspires experimentation.
1172658
Actually it's a question in physics. I will try to explain it anyway:\nassume we have two windings w1 and w2 with  n1 rounds and n2 rounds respectively. If an A.C. voltage of V1 is connected to w1 then a voltage V2 will be induced in w2, satisfying the following equation:\nV1/V2=n1/n2 and for currents we have: I1/I2=n2/n1\nand it doesnt convert ac to dc to do so we should use a rectifier such as bridge rectifier etc
15184
Using Ohm's Law, V=IR, we have 10=I(5).  Solving for I, the current is 2 Amps.
75746
You'll need to provide a little more information in order to have your question answered properly.  AC or DC? Input voltage?  Fixed or variable output voltage? If variable, over what range? If fixed, what is the desired output voltage?  Output current?  How critical is the load regulation?\n\nAs you can see, the answer to your simple question can be a bit complicated :)
919217
Like everything else, it depends.  The concern is that at the maximum current you will draw, there is sufficient voltage at the point of use.  Voltage drop depends on the amount of current, and the resistance of the circuit.  \n\nYou can determine the minimum voltage requirements for whatever you are driving.  Knowing the resistance per foot of various sizes of wire, you could determine the size wire needed.\n\nNow it becomes a matter of economics.  Is larger wire less expensive than a transformer--or two if you are going to maintain the original equipment operating voltage.
554455
general accepted values for residential installations, for lighting branch circuits 20 amperes, for general load convenience outlets 20 to 30 amperes. for industrial is different though, normal rule is if you know how much is the total current required for that branch circuit, say for a motor load, it is approximately 120 percent for circuit breakers and 300 percent multiplying factor for fuses.  hope this will be of help.
717825
if It is A/C Single Phase,Assume V=230,\n10 KVA= 10* 1000* V*A\n       P = V * I * 0.8 ( Power factor)\n       10000 = 230 * 0.8 * I\n          \n             Amps I = 54 A ( For single Phase)\n\nFor Three Phase V= 420 V.\n\nFor DC Supply Neglet the Power Factor
240898
This is stuff I have not worked with in 20 years. LOL. I can not draw this for you here, you can figure it maybe from what I tell you. \n(1) You want a circuit that has say 10V steered to four outputs depending on the control inputs. We will say the control inputs are 0 & 5 volts we are steering 10 volts. You are looking at a circuit with 7 lines. 1 input, 2 control and 4 outputs. The voltage to your controls has 4 possibilites.\n0&0 control volts input 10 volts to output line #1\n0&5 control volts input 10 volts to output line #2\n5&0 control volts input 10 volts to output line #3\n5&5 control volts input 10 volts to output line #4\nThat about all I can say here. May use AND, OR, NOR Gates??\n(2) Is even more complicated and I can not even begin to tell this in words. Hope this helps, I doubt it will, but, I tried.
437730
See http://members.aol.com/logan20/elecspon.html for the equation to use.
324170
the 20 ohm is shorted because the current can go through the switch without going through the reisistor. when it is closed, R =10+1 =11, V =3, Current = V/R = 3/11 amps\n\nbecause direct current cannot cross a capacitor, which is in cd. this is because a capacicotr is plates which are parallel and do not touch. obviously, if the plates do not touch, electricity cannot flow through them. alternating current can go through a capacitor, only because the capacitor keeps discharging
514134
i think this is the equation\nE=VxI\nE is energy. V is volts . I is current which is measured in Amps\nE= 120 x 12.5\nE=1500Watts
341482
Ok break it down:\n1) A power supply converts AC power (110 in the states) to some other required voltage. For this (lab) project I'd presume a DC regulated voltage from, say 1.5 to 15V something like that.\n\n2) Digital and programmable means you'd control the output voltage with some sort of digital signal like up/down buttons, a keypad, or a PC hookup.\n\n3) You are supposed to use an 8051 to accomplish this.\n\nSo there are several ways to do this. One way would be to have the 8051 accept a command to set the voltage and produce a PWM signal. Let's say the PWM signal is a 5V output switched from 0 to 100%. You can use an RC filter to produce 0V to 5V from this signal. If your instructor is nice, you could argue that this meets the criteria -- especially if you use it to drive a pass transistor to develop some serious current (but your voltage is now 0V to 4.3V because of the BE drop).\n\nBut I'd instead use an op amp with gain X3 (plus a little extra) so that I got from 0 to 15.7V and then use the pass transistor. Another idea would be to use the voltage to drive a simple current source which would program a LM317 voltage regulator.\n\nWeb searches on things like LM317, PWM, and "pass transistor" are your friends here.
434630
dont forget the formula I= R/U\nsort them and u will get the answer\n\n Current: 625mA (milli amperes)\nResistance: 19.2 ohms
928978
It wouldn't be easy.\n\nPower supplies for PC's generally produce four outputs: +12v, -12v, +5v, and -5v. Some PC power supplies also produce +3.3v and -3.3v. These voltages are measured with respect to a ground of 0 v. \n\nYour car battery is probably 12v, which means that there is a total of 12v of potential between the + and - poles; so the cathode of your car battery gives -6v and the anode gives +6v with respect to ground. It's very easy to step these voltages down to +-5v and +-3.3v, just put the appropriate resistor into the circuit and there you are. \n\nBut stepping the voltage UP to +-12v is another matter entirely. For that, you will need a transformer of the correct size and winding. Further, you should be aware that most desktop PC's want to consume 100, 200 or even 300 watts, which may easily be more continuous power than your auto battery is designed to give.
789710
15 Amps? Looks like 10 gauge, see the link, take a grain of salt. This site says 15 amps, regardless of voltage. Tough to believe, since we care about heating, which is power, which is P=IV, so stating the current doesn't mention the power. But power is also RI^2, so I guess they know R, so they know power with current squared.
732893
we know that for power, P=IV. we also know that whatever power goes into the transformer comes out of the transformer(conservation of energy). this means that V is inversely proportional to I. or I is inversely proportional to V.\n\nif you already know how much V was stepped up, then just step down the I by the same ratio. for eg, if 110V 10A was transformed to 220V, then the step up ratio is 2. therefore current is stepped down by 2. so current will be 5. try equating 110x10 with 220x5, it is constant.\n\nall of this assumes that the transformer is 100% efficient. if there are losses due to heat, then you multiply the exit current by the efficiency factor. eg, if the trans is said to be 80% effiecient, then the actual exit current would not be 5A but 4A. voltage is not affected by effiency issues.\n\nby the way transformers only work with AC, the guy who mentioned direct currents is thinking of current rectifer not transformer.
261103
10 amps if the voltage difference is 120 volt as usual