order to regulate the amount of current and voltage in a circuit made of resistors particular compound.Series-connected elements limit the current in the circuit, and the parallel connection creates an additional voltage drop, thereby limiting the magnitude of the potential difference to consumers, who are in the same chain.
can use one resistor value desired, but is not always possible to make the necessary calculations to determine the optimal value.Therefore it is advisable to select resistance by combining different quantities.
parallel resistor is made by connecting the beginnings and ends of all elements in a single node.Thus, a scheme where, depending on the value of each element is created by the total voltage drop across the circuit.
total resistance of resistors connected in parallel is calculated by a special formula.
Keep in mind that if you made the parallel connection of resistors, the total resistance of all elements will definitely be less than the smallest resistance included in the circuit.
However, there are some special cases, which can not be forgotten.If the circuit is enabled only two resistors, their total resistance is calculated as the difference between their product and sum: Rmain = R1R2 / R1 + R2.
Another special case is a compound which includes a lot of resistors with the same resistance value.In this case, the total value is determined as the difference value of the number of resistance elements, ie: Rmain = R1 / n.
Since the parallel connection of resistors - two nodes, it is clear that the difference of potential - it is the same as the potential difference between these two nodes.Thus, it is reasonable to conclude that the voltage on each of the elements are equal.It looks like this: U = U1 + U2 + U3 + .... + Un.
If both nodes forming a parallel connection of resistors are connected directly to the terminals of the power supply, the voltage of each of the resistances will be equal to the voltage that generates the source itself: U1 + U2 + U3 + .... + Un = U.
Another feature of Connectionresistance circuit parallel connection is an electrical current.It is distributed through the branches in reverse proportional to the resistance of these regions.In other words, the greater the resistance, the less current, and conversely, the higher the current, the lower the resistance.This is the first Ohm's law: I = U / R.
The total current in a node is the sum of current values in each branch separately.After charges can not accumulate in the nodes, so it should be noted first Kirchhoff's law, which states: "The sum of currents that are part of the node is equal to the sum of the currents that come from it."One can simply say - the sum of the currents at the node is equal to zero.And writes an expression this way: "The sum of the currents is equal to zero."
laws presented here are relevant for circuits without inductance and capacitance.If the resistor is connected in parallel on the same circuit with the coil or condenser, it is necessary to find the impedance of taking into account all the elements.To do this, calculate inductance and capacitance.
