Here's the extremely short answer. Conductors are always full of movable electric charges. Voltage pushes charges through the conductive object which has a certain amount of electrical resistance or "friction," and this heats up the resistive object. The flow rate of the moving charges is measured in amperes, while the transfer of electrical energy as well as the rate of heat output is measured in watts. The electrical resistance is measured in ohms.
First the watts and amperes. Watts and amps are somewhat confusing because these are the names of flows, yet we rarely talk about the STUFF that flows. (Could we ever understand water-flow without first grasping the "water" concept?!) Electric current isn't a stuff. Electric current is the flow of a stuff. What's the name of the stuff that flows during an electric current? The flowing stuff is called "Charge."
what is the relation between volts and amps?
2 answers
Volts measure the force pushing the electrons around in a circuit, and amperes measures how many of them (or how much "charge") flows through any part of the circuit in a fixed time.
In most circuits, (volts)/(amperes) = resistance (in ohms), where the resistance (R) is a constant that depends upon the circuit. That is "Ohm's Law". In AC circuits or circuits with diodes or "solid state" devices, Ohms law does not apply.
In most circuits, (volts)/(amperes) = resistance (in ohms), where the resistance (R) is a constant that depends upon the circuit. That is "Ohm's Law". In AC circuits or circuits with diodes or "solid state" devices, Ohms law does not apply.