The character "C" represents single coil. The characters "CC" represent double coil. (Example : CC-2F) (1) Rated voltage The voltage at which the rated current, brightness and average service life are obtained is referred to as rated voltage. Voltage is mainly decided by length of filament. (2) Rated current The rated current is the current which flows when the rated voltage is applied to the lamp. The current tolerance is kept within �}10%. Current depends mainly on the diameter of filament. (3)Brightness The brightness is obtained when the rated voltage is applied to the lamp. The brightness unit which is usually applied in Japan and Europe is luminous flux (Lm) but in USA the mean spherical candlepower (M.S.C.P.) is used. There is a relation between luminous flux from light source and MSCP as expressed bellow. Although the brightness tolerance is kept within �}25%, in special cases �}10% and �}15% are also applicable. (4) Average life The life is expressed as average time until break down occurs during continuous lighting under rated voltage without vibration and shocks, with voltage fluctuation within �}1%. The life is affected by the efficiency of lamp. The effeciency is calculated by the formula shown below : Generally, a lamp with lower efficiency has a longer life. Because the life of the miniature lamp is very long, the approximate average life determined by the accelerated life test under overvoltage is commonly accepted. In such cases, the life is calculated as the inverse proportion to 12th-13th power of the applied voltage. The current, brightness and life of lamp change depending on applied voltage . Generally, the relation of these factors is expressed as follows : NOTCHING ¡¡ Graph(A) shows the relation between voltage and characteristics. With small current long-life lamps (approx. 100mA or less , 50hrs. or more), some factors other them evaporation of normal tungsten filament affect, resulting in changes differing from theoretical ones. This is due to notching effect. The notching is an appearance of step-shaped or saw-shaped irregularities on the filament surface after the lamp is turned on. There are two types of notching, namely appearance on whole surface of filament and appearance on the part where filament temperature gradient exists. The whole surface notching appears in case of DC lighting. The temperature gradient part notching appears near the anchor and at the connection of filament and lead wire irrespective of AC and DC. As a result of notching the filament diameter reduces, the thinned part is excessively heated, resulting in promoted evaporation of filament and reduction of its life. Especially, in case of DC lighting the life may be reduced below 50% of average life. This abnormal effect affects remarkably the lamps having low luminous flux, low current, and long life. Our factory has succeeded in suppressing the notching by using a combination of tungsten filament material and processing method. As a result, the designed characteristics of lamps having low luminous flux and low current can be obtained without reduction of life. Our factory can supply the notching-proof lamps in addition to standard lamps. [ Shock and Vibration ] Generally, as the lighting time of lamp increases, the filament crystal grows, resulting in embrittlement and reduction of strength. If higher vibration resistance and shock resistance are required, it is recommended to select the lamps having lower rated voltage and higher current. [ Lamp ON/OFF ] Frequent lamp on/off may cause reduction of its life due to influence of rush current . It varies depending on/off interval, frequency, lamp capacity, and efficiency. If detailed information is necessary , contact us. [ Rush Current ] The lamp cold resistance is about 1/10 of resistance in lighting state. According, a significant transient current flows momentarily when the lamp is turned on. This current is called rush current. The quantity and time of rush current vary depending on lamp capacity and efficiency. [ Efficiency and Color Temperature ] Below is shown the relation between lamp efficiency and color temperature. [ Spectral Distribution Characteristics ] Below are shown filament color temperature and spectral distribution. [ Temperature in Lighting State ] While the lamp is lighting, the filament temperature rises remarkably, so that the temperature of glass bulb and socket rises, which may cause adverse infuence upon the lamp life. This problem must be taken into account before use. Below is shown an example of temperature data of glass bulb in the state where the miniature lamp was lighted individually. Glass bulb diameter (mm) Overall length (mm) Rated voltage (V) Current (mA) Power consumption (W) Mount shape Temperature PointA PointB PointC 3.0 6.35 14.0 40 0.56 C-2F 62 62 51 3.0 6.35 14.0 60 0.84 C-2F 76 76 59 4.2 10.0 14.0 40 0.56 C-2F 52 43 45 4.2 10.0 14.0 60 0.84 C-2F 61 63 46 4.2 10.0 14.0 100 1.4 C-2F 88 87 65 4.8 11.0 14.0 100 1.4 C-2F 75 77 62