constant light source

2 constant light source In many occupations it is important that the light incidence at a certain location remains as nearly constant as possible. When the sun appears from behind the clouds (it happens sometimes!), it causes an increase in light in a room or onto an object. Such varying ambient light is tiring on the eyes for many people when painting, reading, and so on. If ambient light does not vary too wildly, the light source described here may offer a solution. The circuit controls a light bulb so that the brightness of the bulb is matched with the incidence of ambient light. The bulb will therefore light more brightly if the sun disappears behind the clouds again. The circuit can of course be connected to the lighting of a living room or study: if it gets darker outside, the lights in the room will then compensate. This circuit is a real solution if you don"t like working or sitting in semi-dark- ness. -4 `.M The principle is fairly simple: a sensor measures both the incid...