There are four general categories of light Source: incandescent lamps, tungsten halogen lamp, fluorescent lamps and LEDs. Three types of light source each has the pros and cons, different people may like the light color and brightness of different light sources, should be due to human. In order to be able to project most of the light onto the desktop, the light source installation position of the writing lamp is usually horizontal or downward.
In the purchase of writing desk lamps, in addition to check their optical performance, should also check the other performance of eligibility.
One pull, two tune, three shakes, four touch. "Pull" refers to the power cord plug out of the socket, forcibly pulling the power cord to the lamp cavity, to see if the power cord is firmly connected. The power cord cannot be detached from the lamp cavity. "Tune" refers to the table lamp to regulate the various work position, adjust, can not make a sound, adjust the position should be able to easily and reliably locked. "Shake" refers to the table lamp to the most unfavorable position, and then gently shake the table lamp placed plane, watch the lamp is easy to overturn, the table lamp smoothness bad, easily overturned. "Touch" refers to the lamp lit a period of time (2 hours) after the use of the hand touch lampshade, such as easy to touch the hot parts of the heat, in case of later use by accidental scald.