Tungsten halogen lamp for slide projector. This size of halogen lamp is suitable for devices that that light moderately large areas, such as a projection screen, but is smaller than the lamps used for television and film studio production. It has a larger and thicker tungsten filament than smaller lamps, used for microscope lamps. This lamp is rated at 250 watts and 24 volts. The power supply is usually direct current (DC), and the lamp has the standard GX6.35 base and connection pins with a separation of 6.35 millimetres.