The change in resistance of tungsten wire has a direct impact on the power of the light bulb. The following is a detailed analysis of this impact:
- The relationship between resistance and power
In a circuit, the relationship between power (P), voltage (U) and resistance (R) can be expressed by the formula P=U²/R (under constant voltage). This formula shows that under constant voltage, the size of the resistance is inversely proportional to the power: the larger the resistance, the smaller the power; the smaller the resistance, the greater the power.
- Change in resistance of tungsten wire
Tungsten wire resistance of new light bulbs: Tungsten wires in new light bulbs usually have higher resistance because their cross-section is thicker and they have not been subjected to high temperatures for a long time.
Resistance changes after long-term use: As the light bulb is used for a longer time, the tungsten wire will sublimate at high temperatures, causing the tungsten wire to gradually become thinner. According to the law of resistance, the thinner the wire (tungsten wire), the greater its resistance. Therefore, the resistance of the tungsten wire in the light bulb will increase after long-term use.
- The impact of resistance change on bulb power
Power drop: Due to the increase in tungsten wire resistance, according to the power formula P=U²/R, under constant voltage, the actual power of the bulb will decrease as the resistance increases. This will cause the brightness of the bulb to decrease.
Luminous efficiency change: Although the power decreases, the tungsten vapor in the bulb may condense on the inner wall of the bulb after the tungsten wire sublimates, reducing the transparency of the bulb and further affecting the luminous efficiency.
- Considerations in practical applications
Bulb design: In the process of bulb design, it is necessary to consider the change of tungsten wire resistance over time to ensure that the bulb can still maintain a certain brightness and luminous efficiency after long-term use.
Bulb replacement: Since long-term use will cause the tungsten wire resistance to increase and the power to decrease, when the brightness of the bulb is significantly reduced, it is usually necessary to replace the new bulb in time.
More details of tungsten wires, please visit website: http://tungsten.com.cn/tungsten-wires.html
Please contact CHINATUNGSTEN for inquiry and order of tungsten needles:
Email: sales@chinatungsten.com
Tel.: +86 592 5129595
