reson why an ideal ammeter have a zero resistance?
931362
resistance opposes the flow of current right and any resistance in this device causes  a  error in the readin of current flowin through the circut ..so ideal ammeter shuld have zero resistance ...\n\n   i=V/(r+R) ....\n   i is the curent in the circut\n   V is potential diff across the circut\n   r is resistance of ammeter \n   R is resistance of the circut(say)\n   to get exact values of i r must be equal to zero
867589
Mechanical measuring devices have some frictional mechanical resistance to movement, so might not be moved at all by small pressures.  That would be an error of 100%.  A manometer has frictional resistance approaching zero, so it is a good choice for getting a measurement with an error which is very small compared to the true value of the pressure.
815817
You must have the CELL CONSTANT to do this properly.\nResistance and Conductance are reciprocals.   But to go from\nConductance to ConductIVITY, you need the Cell Constant.\nIt's different for each probe, and should be easy to find on the probe you're using.   Find that and get back to me.
349619
One end of the galvanometer is connected between P and Q; the other end between R and S.\n\nYou have one sided deflection even after checking for any wrong connections.\n\nIt means proper ratio of resistances is not chosen.\n\nThe resistances cannot be taken at random.  P/ Q must be nearly equal to R/S.\n\nAdjust the resistances so that P/ Q must be nearly equal to R/S.\n\nWhen these ratios differ much you will get one sided deflection.
6099
I may be living in the past but I see transistors every day.  The 2-diode analogy is pretty close to the mark.  They meet at the base, pointing in for PNP and out for NPN.  Check them that way with your multimeter set on diode setting.  If the reading is inconclusive you may have to de-solder them from the circuit.
701756
Resistance, R, is converted to conductance, G, by inversion. \nG = 1/R. The unit was called mho (ohm spelled backwards) when I went to school. But the unit name was changed to Siemens (the symbol is S) when the SI unit changes were made. \n\nSo just take all your readings and do a 1/x calculation with your calculator. And put an S after each result for the unit.\n\nIncidentally, ohmmeters are not very accurate with measurements of such low resistance. The test leads probably have resistance of something like .3 ohms.
913372
It doesn't really have one. Its just a useful way of characterising the battery's behaviour.\n\nBatteries approximate to perfect voltage sources - in other words, the voltage across them does not drop no matter how much current you draw. (By contrast, solar cells approximate to perfect current sources).\n\nOf course, in reality the voltage does drop a little, and drops more the more current is drawn. The relationship is almost a straight line for small currents, and so it is useful to know the rate the voltage drops as the current increases, or dV/dI. Now of course the units of volts/amps is ohms.\n\nWhere this relationship is linear (small currents) you can also usefully include the internal resistance as a fictitious resitance in a circuit - it will do just as well as accounting for the change in voltage (can you see why?).
879048
Resistance = Voltage / Current\n= 1.4/0.8\n= 1.75 ohms.
695376
The resistance of the filament of the lamp varies with temperature. When the filament is at room temperature the resistance is much lower than when it is white hot. \n\nCurrent = V/R. If the voltage is constant and the resistance increases, the current decreases.
284869
In  a given material of a given cross-section, the resistance increases with length.  Now conduction is the opposite of resistance, so the shorter it is, the better it will conduct.  \n\nEs mayor en una corta.
1148859
Simple!\n\nJust a battery, resister, and the diode\n\nThe resister is determined by the size of the battery and the maximum allowable load on the diode. You have to have the diode specs to determine this.
1100598
voltage = current x resistance\nE = I x R  It IS Ohm's law. An easy way to remember the formula and it's configurations is to draw a circle and divide it in half horizontally. Above the line write "E". In the lower half divide the semicircle vertically and write "I" on the left, "R" on the right. It should look something like this:\n                                                     E\n                                                   I    R\nNow just cover up the one you need. and either divide, or multiply.
745543
They are both resistive elements.\nA resistor is a passive component and a transistor is active\n\nA resistor has a fixed resistance that does not depend on signal polarity or amplitude.  It just sits there and does it's job, so it's called passive.\n\nA transistor resistance varies depending on an applied control signal.  It has a third pin dedicated to the control signal input, where a resistor only has 2 pins.  The control pin is what makes transistors active.\n\nThere are other differences of course, in size, polarity, form factor, material, etc.  I limited my answer to the main point of passive versus active.
203751
Resistors are made of elements(metal,etc) which resist the flow of electrons through them to a acceptable limit. This is because of the interaction of the electrons with the crystal lattice and ions in the resistor. \n\nResistors have value of resistance between that of Good conductors and insulators.\n\nCommonly carbon is used in resistors.
306573
Same as the way to test a diode. One pin is negative and the other is positive. Set the multimeter to test resistance.\n\nTRansistor is a two diode cirtuit, you have to determine if this is PNP or NPN transistor. Use the negative probe and connect to N or negative pin, use the positive probe of the multimeter and tap the P or positive pin of the transistor. Correct polarity test should show a resistance, if none then its busted.\nWhile reverse polarity should show a ZERO resistance, anything else shows a short circuit.\n\nSCR or silcon control rectifier is like two diode all regulating current outward, test procedure is the same, basic is like testing diode, correct polarity should show a flow in current or a resistance, while reverse polarity test should show a ZERO resistance or no flow.\n\nKnow the part polarity pin first.
344162
It depends upon the design of the particular meter and is specified by the manufacturer as the amount of current required for full-scale deflection of the meter. This commonly falls in the microamp or millamp range.\n\nAn external resistor called a shunt may be placed in parallel across the meter to multiply its full-scale range by several magnitudes for measurement of much larger currents using the same meter.\n\nWK
765543
try\nhttp://www.dir.ca.gov/title8/2395_42.html\nsection b\n\nGrounds are also tied to the cold water pipes and gas pipes.\nmake sure all circuits are dry and checked with a insulation resistor tester (megger).Readings above 2 Mega Ohms should be OK.