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why do light bulbs glow after turning them off Scientific Knowledge

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why do light bulbs glow after turning them off?

  1. After the bulb heats up and emits afterglow – incandescent or halogen lamps work for a period of time, the filament will heat up and emit a glow, and even if the power is turned off, the filament will take some time to cool down before it is completely extinguished. This is a normal phenomenon, will not affect the lamp and circuit.
  2. The lampholder contact residual charge – the metal contacts of the lampholder will accumulate a certain charge during the process of energizing. After the switch is closed, this charge will take some time to release and dissipate, during which time it will continue to power the bulb and make it glow. This is also a normal situation, the light will go out after the charge is released, no need to worry.
  3. switch contacts poor contact – switch contacts aging or damaged, can not completely break the circuit, will lead to a certain amount of current to continue to flow through the bulb, so that it emits a weak light. The switch needs to be inspected and repaired or replaced if necessary.

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The common causes of poor switch contacts are

  1. contact aging – the contact surface oxidation, corrosion, contact area reduction, can not fully conduct or disconnect the current.
  2. contact damage – the contact mechanical force is too large resulting in deformation or fracture, can not work properly.
  3. Loose contact – contact connection bolt or nut is loose, resulting in a gap between the contacts, the current can flow through the gap.
  4. contact stain – contact surface stained, dust, increased contact resistance, resulting in poor contact.

To check and repair poor switch contacts, the following methods are used.

  1. Inspect the switch contacts to determine the degree of contact aging, damage, or looseness. If necessary, clean the contact surface.
  2. Tighten the contact connection bolts to ensure a reliable connection and tight contact.
  3. Gently lift or tap the switch to check if the contacts can be opened and closed properly. If the switch cannot be repaired, replace the switch.
  4. temporarily bypass the faulty switch, directly connect the lamp to the power supply, check whether the problem is solved. If yes, the switch contacts are bad, replace the switch. 5.
  5. If the above methods can not solve the problem, contact an electrician for a more professional overhaul. Safety first, to avoid the risk of electric shock or fire.
  6. Circuit breaker failure – The circuit breaker is unable to completely break the circuit supply, causing the bulb to remain energized and glowing. The circuit breaker needs to be checked and repaired by an electrician. This is a more serious fault and poses a risk of electric shock and fire.
  7. short circuit inside the fixture – A short circuit inside the fixture causes current to flow through a path that does not pass through the filament, causing the filament to glow. This means the fixture is damaged and needs to be replaced to prevent electric shock and fire hazards.

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led lights Wire failure

If the ground wire does not make good contact and does not work properly, it can cause the following problems.

  1. the circuit is unable to discharge excess charge – during the power supply a small amount of static electricity or other excess charge is generated and relies on the ground wire to be discharged to earth. If a ground fault occurs, the charge can collect on the line and equipment, producing certain effects such as faint light or noise.
  2. Insulation damage is difficult to detect – Under normal conditions, if the insulation of the power line is damaged, the grounding protection can quickly conduct the leakage to earth, thus breaking the circuit to prevent the danger. If there is a ground fault, the protection cannot be triggered even if the line insulation has been damaged, making it difficult to detect the potential hazard.
  3. the risk of electric shock or fire – in the most serious cases, a ground fault can lead to the inability to break the faulty circuit, if leakage or short circuit occurs, may lead to electric shock, fire and other accidents, resulting in injury or property damage.

Therefore, if you find that the lights keep flashing for no reason, the ground fault is a very likely cause, need to focus on checking.

led Bulbs Check the following methods.

  1. check the socket, switch, electrical grounding wire at the entry line, to ensure that the connection is secure, no broken wire or corrosion.
  2. Use the ground fault detector to check the overall grounding impedance of the power supply line to ensure that it is within the specified range. If it is out of range, it means there is a problem with the grounding wire.
  3. temporarily remove the grounding wire of an outlet or appliance and observe whether the fault disappears. If so, that the fault equipment grounding problems. Then restore the grounding wire to confirm that the fault disappears.
  4. If the above methods cannot determine or repair the fault, contact a professional electrician to check the overall grounding of the distribution line to eliminate the root cause of the fault.
  5. As a preventive measure, regularly check all obvious grounding wires in the house, such as the connection status of the grounding wire at the main entry line, distribution box, socket, electrical entry line, etc. Small wins big, to eliminate the potential safety hazards.

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Grounding protection is vital to any electrical system. Once a grounding fault is found, it is important to pay attention to it and check and repair it as soon as possible to avoid dangerous accidents. If there is any uncertainty, contacting KOSOOM an electrician is the best led lighting solution.

At lastly, the light bulb off after a short period of time issued afterglow or faint light is normal, but if the light is too long or fluorescence is very strong, it is likely that the above causes, especially the latter three cases are more serious, need to be timely inspection and repair. For safety reasons, for any lamps and lanterns such problems, the best solution is to contact an electrician to check to ensure that there is no circuit or lamp failure.If you want to know about track lighting solutions, follow us

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