Between the current and tension there is directly proportional dependence described by the law of Ohm. This law defines communication of current, tension and resistance on the site of an electrical circuit.
Instruction
1. Remember what is current and tension. - Electric current is an ordered current of charged particles (electrons). For quantitative definition in physics size I called current is used. - Tension of U is a potential difference on the ends of the site of an electrical circuit. This distinction forces to move electrons, like a liquid stream.
2. Current is measured in amperes. In electrical circuits current determine by the device the ampermeter. Unit of voltage is the volt, it is possible to measure tension in a chain by means of the voltmeter. Collect the simplest electrical circuit from a source of current, the resistor, the ampermeter and the voltmeter.
3. At short circuit of a chain and passing of current on it write down indications of devices. Change tension on the ends of resistance. You will see that indications of the ampermeter will grow with increase in tension and vice versa. Such experience shows directly proportional dependence between the current and tension.
4. Electric current is similar to a liquid stream. But charged particles move not in an empty pipe, and on the conductor. Material of the conductor has significant effect on the nature of this movement. For the quantitative description of this influence size R - resistance of an electrical circuit serves. Unit of measure of resistance is the Ohm.
5. Current of subjects is more, than tension and than less resistance of the site of a chain is more. This dependence is described by the law of Ohm: I = U/R.
6. For alternating current directly proportional dependence on tension remains. Alternating current is electromagnetic oscillations of harmonious (sinusoidal) character with a frequency determined by tension source. In a complete electrical circuit with different resistance the communication between current and tension is also described by the law of Ohm.