Sometimes it is necessary to increase force of the current proceeding in an electrical circuit. In this article the main ways of increase in current without use of difficult devices will be considered.
It is required to you
- Ampermeter
Instruction
1. According to the law of Ohm for electrical circuits of a direct current: U=IR, where: U - the size of tension given on an electrical circuit, R is the full resistance of an electrical circuit, I - the size of the current proceeding on an electrical circuit, for determination of current it is necessary to divide tension brought to a chain on its full resistance. I=U/RSootvetstvenno to increase current, it is possible to increase tension given on an entrance of an electrical circuit or to reduce its resistance. Current will increase if to increase tension. Increase in current at the same time will be in proportion to increase in tension. For example, if the chain with a resistance of 10 Ohms was connected to a standard battery of 1.5 Volta, then the current proceeding on it made: 1.5/10=0.15 A (Ampere). At connection to this chain of one more battery of 1.5 V the general tension will become 3 V, and the current proceeding on an electrical circuit will raise up to 0.3 A. Connection is carried out "consistently, that is plus of one battery joins minus of another. Thus, having connected enough power supplies is consecutive, it is possible to receive necessary tension and to provide course of current of the necessary force. Several sources of tension, united in one chain, are called the battery of elements. In life such designs are usually called "batteries (even if the power supply consists of only one element). However in practice the increase in current can differ a little from tension rated (proportional to increase). Generally it is connected with the additional heating of conductors of a chain happening at increase in the current passing on them. At the same time, as a rule, there is an increase in resistance of a chain that leads to decrease in current. Besides, increase in load of an electrical circuit can bring to it "to burn-out or even ignition. It is necessary to be especially attentive at operation of household devices which can work only at the fixed tension.
2. If to reduce the full resistance of an electrical circuit, then current will also increase. According to the law of Ohm the increase in current will be in proportion to reduction of resistance. For example, if tension of the power supply was 1.5 V, and resistance of a chain was 10 Ohms, then on such chain there passed electric current of 0.15 And. If then resistance of a chain to reduce twice (to make equal 5 Ohms), then the current proceeding on a chain will increase twice and will make 0.3 Ampere. An extreme case of reduction of resistance of loading is short circuit at which resistance of loading is almost equal to zero. Infinite current at the same time, of course, does not arise as in a chain there is internal resistance of the power supply. More considerable reduction of resistance can achieve if strongly to cool the conductor. Receiving currents of huge force is based on this effect of superconductivity.
3. For increase in force of alternating current various electronic devices, generally - the current transformers used, for example, in welding machines are used. Force of alternating current increases also at reduction in the frequency (as owing to superficial effect the active resistance of a chain goes down). If at a chain of alternating current there are active resistance, then current will increase at increase in capacity of condensers and reduction of inductance of coils (solenoids). If in a chain there are only tanks (condensers), then current will increase at increase in frequency. If the chain consists of inductance coils, then current will increase at reduction of frequency of current.