How do we use resistors, is there any formula

1.Resistor use: Resistor is one of the most widely used basic components in electrical and electronic equipment. It is mainly used to control and regulate the current and voltage in the circuit, or as a load that consumes electrical energy.

2.There are different ways to classify resistors.

According to the material, there are different types such as carbon film resistance, cement resistance, metal film resistance and wirewound resistance; According to the power, there are 1w w 8, 1w w w, 2w and other rated power resistance; According to the accuracy of the resistance value, there are ordinary resistors with an accuracy of 5%, 10%, 20%, etc., and precision resistors with an accuracy of 2%. The category of resistor can be identified by the appearance marking.

There are many types of resistors, which are usually divided into three categories: fixed resistors, variable resistors, and special resistors. In electronics, fixed resistors are the most widely used.

The fixed resistors can be divided into many categories according to their manufacturing materials, but the commonly used and common ones are RT type carbon film resistors, RJ type metal film resistors, RX type wirewound resistors, and chip resistors that have been widely used in recent years. The model naming is very regular, the first letter r stands for resistance; The meaning of the second letter is: T carbon film, J metal, X-ray winding, these symbols are the first letter of Hanyu Pinyin.

In the old-fashioned domestic electronic products, it is common to see the resistor coated with green paint on the outside, that is, the RT type. The red resistor, on the other hand, is RJ type. In general, in old-fashioned electronic products, green resistors are the majority.

Why? This involves the issue of product cost, because although the metal film resistor has high precision and good temperature characteristics, the manufacturing cost is also high, while the carbon film resistor is particularly cheap and can meet the requirements of civilian products. Of course, resistors also have power.

The common one is the 1 8 watt "color ring carbon film resistor", which is the most used in electronic products and electronic production. Of course, in some miniature products, a resistor of 1 16 watts will be used, which is much smaller. The second is the miniature chip resistor, which is a member of the SMD component family, which used to be mostly seen in imported micro products, and now electronic enthusiasts can also buy domestic products for making small electronic devices.

3.Calculation formula:

Concatenation: r=r1+r2+ rn

Parallel: 1 r=1 r1+1 r2+ 1 rn Two resistors in parallel can also be expressed as r=r1·r2 (r1+r2).

Definition: r=u i

Determinant: r = l s ( represents the resistivity of the resistor, which is determined by its own properties, l represents the length of the resistor, s represents the cross-sectional area of the resistor).

Formula for resistor calculation:1. r= l s (where denotes the resistivity of the resistor.

It is determined by its own properties, L represents the length of the resistance, and S represents the cross-sectional area of the resistance).

2. Definition: r=u i.

3. Series circuit.

Total resistance in : r=r1+r2+r3+......rn。

4. Parallel circuit.

Total resistance in : 1 r = 1 r1 + 1 r2 + ......1/rn。

5. Through electric power.

Find the resistance: r=u p; r=p/i²。

Illustrate the delay: In physics, resistance indicates the magnitude of a conductor's resistance to an electric current. The greater the resistance of a conductor, the greater the resistance of the conductor to the current. Different conductors, the resistance is generally different, and the resistance is a characteristic of the conductor itself.

Factors influencing the resistance value of a resistive element:

1. Length: When the material and cross-sectional area are the same, the longer the length of the conductor, the greater the resistance.

2. Cross-sectional area: When the material and length are the same, the smaller the cross-sectional area of the conductor, the greater the resistance.

3. Material: When the length and cross-sectional area are the same, the conductor resistance of different materials is different.

4. Temperature: For most conductors, the higher the temperature, the greater the resistance, such as metal; For a few conductors, the higher the temperature, the lower the resistance, such as carbon.

Suggestion: Just memorize the most basic physical formulas, and then use the basic deduction to go through the complex formulas, so that even if you forget them, you can deduce them immediately!

1.Resistance: r= l s

2.Ohm's Law: i u r

3.Series circuits.

r＝r1＋r2

4.Parallel circuits.

p i2 r u 2 r (pure resistance formula) q i2rt universal formula) q uit pt uq power u2t r (pure resistance formula) w uit pt uq (universal formula) w i 2rt u 2t r (pure resistance formula).

1. Current intensity.

i q power t

2 Resistance: r = l s

3 Ohm's law: i u r

4 Joule's law.

Q i2RT Universal Formula).

q uit pt uq power u2t r (pure resistance formula) 5 series circuit:

i＝i1＝i2

u＝u1＋u2

r＝r1＋r2

u1 u2 r1 r2 (partial pressure formula).

p1/p2＝r1/r2

6 parallel circuits:

i＝i1＋i2

u＝u1＝u2

1 r 1 r1 1 r2 [ r r1r2 (r1 r2)]i1 i2 r2 r1 ( Dividing the Atom Frontal Noise Flow Formula).

p1/p2＝r2/r1

7. Constant Resistance:

i1/i2＝u1/u2

p1/p2＝i12/i22

p1/p2＝u12/u22

8. Electric power. w uit pt uq (universal formula) w i 2rt u 2t r (pure resistance formula) 9 electric power quiver:

p w t ui (Universal Formula).

p i2 r u 2 r (pure resistance formula).

p=u2i (for pure resistive parallel circuits).

Joule's Law: (When the circuit is a purely resistive circuit.)

When q=w) home circuit trunk current: i= p u look at the nameplate to find the current of the normal operation of the electrical appliance: i=p u look at the nameplate to find the resistance:

r=u2 p series circuit: i=i1=i2 u=u1+u2 r=r1+r2(r=nr0).

Base Macro Parallel circuit: i=i1+i2 u=u1=u2 (pure parallel circuit) common (for simultaneous series or parallel circuits): w=w1+w2 p=p1+p2

The resistance of a conductor to an electric current is called the resistance of the conductor. Resistance (usually denoted by "R") is a physical nucleus that represents the magnitude of a conductor's resistance to an electric current in physics. The greater the resistance of a conductor, the greater the resistance of the conductor to the current.

Different conductors, the resistance is generally different, and resistance is a property of the conductor itself. The resistance of a conductor is usually represented by the letter r, and the unit of resistance is ohm, referred to as ohm, and the symbol is .

Define the formula: r= l s

Variation of Ohm's law: r=u i

Resistance series: r=r1+r2+r3+.rn

The formula for calculating the resistance is: r u i, where u represents the voltage and i represents the current; r l s, where denotes the resistivity of the resistor, is determined by its own properties, l denotes the length of the resistor, and s denotes the cross-sectional area of the resistor.

When the electric charge moves in the conductor, it is subject to the collision and friction of other particles such as molecules and atoms, and the result of the collision and friction forms an obstacle to the current of the conductor, and the most obvious feature of this hindrance is that the conductor consumes electrical energy and generates heat (or emits light). This obstructive effect of an object on an electric current is called the resistance of that object.

Importance. As one of the most important parameters of the battery, the internal resistance is closely related to the capacity, which not only reflects the current state of charge of the battery, but also reflects the degree of deterioration of the battery, and its change reflects the performance and life of the battery. Therefore, it is one of the effective schemes for battery maintenance to measure the performance of the battery and realize the maintenance of the battery by using the internal resistance detection method.

The internal banquet resistance measurement can not only be used for the daily maintenance of the battery, but also for the engineering acceptance of the battery pack, especially for the battery pack selection of various communication operators.

If the internal resistance equalization index is added at the time of battery acceptance, the monomer with high or low internal resistance value is divided into the rent, and the cell with voltage balance, sufficient capacity and uniform internal resistance value is selected to form the battery pack, which can greatly extend the service life of the battery pack.

Similarly, the battery of the same nominal capacity produced by battery manufacturers at different technical levels, its internal resistance is not the same, the smaller the internal resistance value, generally speaking, the higher the process level, the higher the technical content, so by measuring the internal resistance value of the battery of the same nominal capacity produced by different manufacturers, it can be used as a valuable index basis for battery selection.