Confusion

2011 April 7
by roma

So I happened upon a site with an explanation of voltage that may resolve my confusion and also give me a more well-rounded understanding of electricity.

An intuitive way of defining voltage is the electrical potential energy per unit charge. So, if I connect a 12 volt battery to a load, energy will be transferred to the load. The exact amount of energy transferred will be the product of the voltage and the charges going through the load.

In fact, it's from here that the P = EI formula is derived. Voltage (E) is the electrical potential energy per unit charge (coulomb). If we multiply E by the current (unit charges / second), then we get the energy per second. That is equal to the power.

An example with a battery and two loads wired in series is given. The question is:

After the current goes through the battery, it then flows through Element #1. Element #1 has 9 volts across it. How much energy is transferred to Element #1 as the charge flows through it?

The word that got me was "9 volts across it". So loads also somehow have voltage associated with them?

One Response leave one →
  1. roma permalink*
    April 20, 2011

    The latter definition of voltage is not complete. It is imperative to include the idea of measuring the electrical potential energy per unit charge between two points. Thus, loads have certain voltages across them.

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