2 November, 2013

Voltage Troubleshooting

If voltage is the amount of energy available from the energy source, why isn't the voltage meter placed near the power source, but the resistor? THANKS. Basically… Voltage (or potential difference) is measured between two points in a circuit . A voltmeter measures the energy being transferred to/from each Coulomb of circuit electrons passing between the two points. If the voltmeter is connected across (between) the the terminals of an energy source (eg battery) it measures the electrical energy gained by each Coulomb of electrons ( 6. 25^18 electrons) passing from the supply . A voltmeter connected across the terminals of a circuit component measures the energy being transferred to that component (eg . As heat,KE) per Coulomb of passing charge. 1V (pd) = 1J/C of energy transfer. You connect the voltmeter between the points in a circuit where you wish to measure the energy transfer in J/C.

The fundamentals of current and voltage. Explanations of the units Amps, Volts, Coulombs per second and Joules per Coulomb. Helpful articles:

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  1. Grace Robot October 31, 2013 at 10:27 am #
    The volt meter is place across a load (resistance) or a power source but not "near" either. You can place a volt meter across a source of power but all you would read is the voltage drop across the power supply which may not be the same as the voltage available to the load. For instance, a battery has an internal resistance due to the processes associated with chemical generation of electricity. If you place a volt meter across the battery (and the battery is good) you will read the full rated voltage of the battery, but when you hook it to a circuit, you will actually see a little less voltage droped across the circuit. If you want an accurate measure of how much voltage is dropped across a load, you have to put the volt meter across the load.