How manufacturer make light bulb or switch for a specific voltage? How it is determined that the light bulb will work at the maximum specific voltage?

  • 2
    \$\begingroup\$ Because they have about two centuries of data to back them up, including 200 years of field reports, so the MTBF reports are very accurate. Tungsten, CCFL and LED lights are very well known mathematically. \$\endgroup\$
    – user105652
    Jun 8, 2018 at 5:42
  • \$\begingroup\$ Light bulbs are very old. When you lack the computational tools to figure out things like this, you make samples and test them. Adjusting parameters until you achieve a design you are happy with. \$\endgroup\$
    – user57037
    Jun 8, 2018 at 6:00
  • \$\begingroup\$ Two words: type tests. \$\endgroup\$
    – winny
    Jun 8, 2018 at 6:03
  • \$\begingroup\$ Your Title question is too broad in scope for a global answer, so for sanity's sake we will confine the subject to loads that intentionally produce light in a controlled way. \$\endgroup\$
    – user105652
    Jun 8, 2018 at 6:49

1 Answer 1


The maximum (and minimum) voltages etc are ratings.

A rating means that the manufacturer asserts that when operated under specified conditions, the device will give a specified performance. They back this up by testing many, many components over thousands of hours.

For instance an incandescent light might have the specified performance of >1000 hours lifetime. This will set the maximum voltage, as a hotter lamp will burn out faster.

With a switch, the key specification will again be lifetime, as the contacts spark and erode a little every time the circuit is opened. The sparking will be worse at higher voltages, and higher contact currents. Some switches have two ratings, a heavy load and a light load rating. I saw one recently which claimed to give 10^7 operations at 100mA, and 10^5 operations at 10A.

  • \$\begingroup\$ did edison inscribed any voltage current rating on his first light bulb if not when the trend began? \$\endgroup\$
    – JNS
    Jun 8, 2018 at 14:58
  • \$\begingroup\$ anyway thank you for answering to previous question your valuable time counts \$\endgroup\$
    – JNS
    Jun 8, 2018 at 14:59

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