Is a desk lamp a pure resistance circuit Is a light bulb a pure resistance and why

Incandescent lamps convert more than 99% of electrical energy into heat, with very little conversion into light energy. Therefore, in secondary school electrical calculations, 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 electricity than CFLs (which convert almost all of the electrical energy into light).

A pure resistive circuit is a circuit that has only resistive elements, or inductive and capacitive elements, except for the alternating power supply, but their impact on the circuit is negligible. Voltage and current are at the same frequency and in the same phase. Resistance converts all the energy obtained from the power supply into internal energy, and this kind of circuit is called a pure resistance circuit.

Be. It doesn't matter if it's methodical or not. As long as electrical appliances do not convert electrical energy into mechanical energy, most of them are pure resistance.

Pure resistance refers to a circuit that converts all electrical energy into heat.

The current table lamp is not a lamp that emits light by heat energy, isn't there light energy or chemical energy?

This is the case, like the incandescent lamp, it is heated by the thermal effect of the resistance to emit bright light, which is pure resistance (the light here is a form of energy transmission, the main reason is the heating of the filament), if our household energy-saving lamp (fluorescent lamp) This is a cold light lamp, and the main difference between it and the front is probably seen, their luminescence principle is to excite the electrons after the power is turned on to make the phosphor energy of the lamp increase and then release the process (first explain it roughly, The specifics are quite complicated). In this way, it is not a pure resistance, the reason is similar to that of an electric motor, part of the energy is directly converted into light energy, not all internal energy.

Yes, the power consumption of adjusting the brightness remains the same

That depends on whether you're an incandescent lamp or a fluorescent tube. An incandescent lamp converts electrical energy into internal energy and emits light in an incandescent state. A fluorescent tube is a phosphor that emits white light from mercury vapor that emits ultraviolet light onto the tube wall, which is not considered a pure electrical resistance.

Light bulbs are not all purely resistive, only resistance filament bulbs, such as incandescent lamps, are purely resistive; There are some energy-saving lamps that are made by the principle of gas discharge or electrode discharge, which do not belong to the pure resistance category, such as LED bulbs and various energy-saving lamps.

Pure resistance bulbs emit light by heating up a resistance wire, which has a high heat loss and low luminous efficiency. Energy-saving lamp is a kind of cold light lamp, which has high luminous efficiency, so it is called energy-saving lamp.

Summary. Kiss! The resistance wire of the table lamp is ohm.

Kiss! The resistance wire of the table lamp is ohm.

Kiss! The normal lamp gear resistance is the ohmic line argument. The electrical power of a normal desk lamp is 50 watts and the voltage is 220 volts. According to the formula of electric power stove p=ui, i=p u=50 watts, 220 volts=amps.

According to Pebu Ohm's law i = u r, r = u i = 220 volts ampere = ohm, so according to the electric power formula and laugh and ohm's law substitute the known conditions, the resistance of the normal table lamp is ohm.

A purely resistive circuit is a circuit that has only resistive elements except for the power supply, or inductive and capacitive elements, but their influence on the circuit is negligible. Voltage and current are at the same frequency and in the same phase. Basically, as long as there is no conversion of electrical energy other than internal energy, this circuit is a pure resistive circuit.

Circuits with light bulbs can be approximated as purely resistive circuits, because incandescent lamps convert more than 90% of electrical energy into heat, and very little into light. However, there are energy-saving lamp circuits that belong to non-pure resistance circuits, because most of the energy of energy-saving lamps is converted into light energy, so energy-saving lamps belong to non-pure resistance circuits.

If the resistance passes through a certain part of the circuit, this part of the circuit converts all the resistance into internal energy, and this part of the circuit is a pure resistance circuit. Incandescent bulb circuits are purely resistive circuits.

The light emitting of the bulb is that the filament heats up to a certain high temperature before emitting normally, and the loss of electrical energy is mainly heated, for example, bath bombs use bulbs for heating.

Pure resistive circuits are circuits that only generate heat. For example, the light bulb, in addition to the pure resistance circuit, there are also non-pure resistance circuits, while heating, there will be other forms of energy, motors, etc.

Incandescent lamps belong to purely resistive circuits.

The bulb is a load device as a whole.

The filament is a model of a load element, which is the resistor.

In general, filaments are treated as pure resistance.

Because the length of the filament is very short, shorter than a wire, the electromagnetic inductance is less than that of a wire, and it can be ignored that ordinary incandescent bulbs do not have an inter-plate structure, so they have no capacitance.

Special bulb lamps may come with ballasts, capacitors and arc extinguishing and other components, so special treatment is required, but the non-incandescent lamps and other non-incandescent lamps that we use today cannot simply measure the resistance, because they must be at a standard voltage to present the rated parameters.

The bulb is a pure resistance because the filament of the bulb acts as a resistor.

It can be regarded as a pure resistance (resistance that only heats up), like a water dispenser, the high temperature of the bulb is about 1000 degrees, and the light it emits is negligible

The light emitted by the bulb is a resistor that converts electrical energy into light.

So the circuit that connects the small bulb is really a pure resistive circuit.

And here it mainly depends on whether there is heat energy generated and used as the main product, if there is a non-pure resistance circuit.

In junior high school physics, the light bulb is treated as a pure resistive circuit, because when the light bulb emits light, nearly 90% of the electrical energy is converted into internal energy.

Count! A pure resistive circuit is in a state of energizing, and there is only heat generation and no mechanical energy to the outside, and the motor is not.

Moreover, the small experimental bulb is composed of resistance wires

Electric light bulbs are usually used in the past, and incandescent light bulbs are purely resistive electrical appliances.