Does a light bulb belong to a type of resistance, and is a small bulb a pure resistive circuit

Regardless of the type of bulb, it is a type of resistance, and resistance is only the earliest definition of blocking the flow of current.

According to your understanding, it means that satisfying r=v i is the resistance, and satisfying this condition is also called pure resistance, and the incandescent lamp satisfies this condition, although the incandescent lamp shines and heats, it is all the conversion of energy, and the resistance value of the resistance is also in the cold state and the resistance value in the hot state is small, which has nothing to do with whether it is a resistance or not. Therefore, incandescent lamps are resistive. It is also called linear pure resistance (very small inductive reactance).

Fluorescent lamps, halogen lamps, etc. contain reactance capacitive reactance, which is also a resistor, but the magnitude of the resistance is related to the frequency, which is equivalent to a complex network of pure resistance plus reactance. Reactance is to distinguish ordinary resistance and describe its characteristics and inductive reactance, capacitive reactance, at present, many energy-saving lamps, electronic ballasts are used semiconductor devices, the calculation of current and voltage can not be calculated by r=v i, the calculation power can only use the method of integration, therefore, this kind of bulb belongs to nonlinear resistance, to meet the law of dynamic resistance.

The light bulb is not a pure resistance, pure resistance is an electrical appliance that converts all electrical energy into heat energy, and the light bulb not only heats but also emits light. However, it is generally regarded as a pure resistor in junior high school.

Yes, it is a type of electrical appliance.

Yes, this is obvious, especially since the incandescent lamp generates heat because it is a resistor.

Motors, electric fans, etc., in addition to generating heat, also do external work, so these are non-pure resistive circuits. Incandescent lamps convert more than 90% of electrical energy into heat, with very little conversion into light. Therefore, in the calculation of secondary school applications, incandescent lamps are also approximated as pure resistance.

Energy-saving lamps, on the other hand, convert most of the energy into light energy, so energy-saving lamps are non-pure resistive circuits. This is why incandescent lamps consume far more power than energy-saving lamps.

As long as it conforms to Ohm's law, it doesn't matter what energy it converts into energy, whether it is kinetic energy, chemical energy, or light energy. As long as the current phase and the power supply are consistent, it can be regarded as a pure resistive circuit if it conforms to Ohm's law. Because that's what you can do in terms of calculations and analysis.

Of course, in the circuit with the existence of motors, part of the electrical energy is converted into kinetic energy, and the phase can be balanced after capacitance compensation, but they cannot be regarded as pure resistance circuits when analyzing, and the relationship between voltage and current and resistance is wrong.

Resistance circuit features:

When another resistor and another component, such as a light bulb, are in series in a circuit, the current flowing through the resistor and the bulb is the same, and the sum of the respective voltages of the resistor and the bulb is equal to the total voltage of the resistor and the bulb as a whole. In this case, the resistor acts as a voltage divider.

When a resistor and another component, such as a light bulb, are in parallel in a circuit, the voltage across the resistor is the same as the voltage across the bulb, and the sum of the current flowing through the resistor and the current flowing through the bulb is equal to the total current flowing through the resistor and the bulb. In this case, the resistor acts as a shunt. <>

The bulb of the bulb is about 5 ohms.

The resistance of a bulb changes with the temperature and the length of use. Generally, the older the bulb, the greater the resistance, and the higher the temperature, the greater the bulb resistance. However, the specific resistance of the bulb should be measured by the rated voltage and power written on the bulb, or by voltammetry.

Bulb Selection Tips:

Look at the brightness. When choosing a light bulb, many consumers feel that the brighter it is, the better the quality of the bulb. In fact, this is a big choice misunderstanding, because too bright lights will make people dazzling, and it is easy to cause damage to eyesight, especially easy to develop irritable, withdrawn, and irritable personality.

Therefore, when choosing lamps and lanterns, it is necessary to combine the lighting environment and refer to the light index of the product to choose.

2. Consider the area and floor height. The use of light bulbs has a lot to do with the space area and floor height, so you must confirm it before buying to avoid the situation that the area is too large and the wattage of the bulb is insufficient. To put it simply, with an area of 25 square meters and a floor height, a 23W bulb is sufficient.

3. Select according to color temperature. Color temperature, simply put, is the temperature of a color, which refers to the color change felt by the human eye under different energies of light waves, which is expressed in k (Kelvin). Normally, when the color temperature is 5500K, red, green, and blue can be balanced, and white light is produced after mixing, and the color of the illuminated object is also more realistic, close to the color in natural light.

4. Look at the lamp beads. The core components in the lamp beads have different luminous rates and luminous angles of different qualities and models. Most of the lamps on the market today are single crystal beads, which are a simple crystal.

The light efficiency of the double crystal lamp bead is relatively high, and the light life will be relatively long. <>

The bulb resistance is negligible because the filament is very short in length, shorter than a wire, so the electromagnetic inductance is less than that of a wire and can be ignored. When measuring its voltage, the impedance of the voltmeter is very large, and it can be regarded as an open circuit when connected to the circuit, and the current flowing through it is negligible.

The light bulb, which refers to the lighting source that emits light and heat through electrical energy, was invented by Henri Goebbels in fact to find a suitable material, that is, the invention of the practical incandescent lamp, and the light bulb appeared as early as 1854. The most common function of the bulb is to illuminate the abrasive limbs. With the development of society, the use of light bulbs has also played a different role, and it may have been blind at first to provide convenience for production and life.

The inert gas used in modern light bulbs is usually argon, which greatly reduces this loss of tungsten. When a tungsten atom evaporates, it collides with an argon atom and since the noble gas usually does not react with other elements, there is no combustion reaction.

Common features. The most common function of a light bulb is lighting. With the development of society, the use of light bulbs also plays a different role, initially may be to provide convenience for production and life, but with the progress of society, there have been obvious changes in the use of light bulbs, and there are "automobiles, landscaping, decoration" and other functional lamps for different purposes.

The above content refers to Encyclopedia - Light Bulbs.

Because p=iv, v=ir

So r=v 2 p

r: the resistance of the bulb, unit: ohms denoted by the symbol; This resistance is the resistance during normal operation, and it is normal to measure the resistance with a multimeter when it is cold.

V: the rated operating voltage of the bulb, unit: volts are represented by the symbol V;

P: The rated power of the bulb in watts is denoted by the symbol W; In everyday language, tile is said to be a branch light, that is to say, a lamp with 40 lights is 40w

By the way, p=iv is the electrical power, v=ir ohm's law.

Ohm's law can also be applied to the calculation of two known parameters to find another parameter between the current, voltage, and inductive (capacitive) resistance of the capacitive load and the inductive load in an AC circuit. Due to the phase problem, the electrical power is not suitable.

You calculate it this way:

For example, how to calculate the resistance of a 220V and 60W light bulb?

The formula for calculating single-phase power is as follows:

1) p=iu(watts).

2) p=i 2r (watts).

3) p=u2r(watts).

The bulb has told you the voltage U=220V and the power P=60W, so obviously we should use the formula (3)P=U2 R (watts) to calculate the resistance: R=U2 P=220x220 60=807 (ohms).

Knowing this method, you can calculate 200W, 100W, 40W, 25W, and their resistances are 242, 484, 1210, and 1936 ohms respectively.