| 摘要 |
<p>The projection lamp control system for, e.g. diapositive projection equipment, has a photoelectric receiving device (Ph) which receives light for the lamp, to give actual value output signals corresp. to the brightness of the lamp. This is followed by an amplifier (1) and a subtracting amplifier (2) and an adding amplifier (3) all in series with a phase controller (5) for the triac which supplies the lamp. A ramp generator (4), providing a time function for controlling the brightness of the lamp, has an output connection to the second input of the subtracting amplifier and also to the second input of the adding amplifier. The difference between the actual and nominal values for the lamp brightness is then used to control the phase controller to regulate the lamp. The time function is either a rising or falling ramp function.</p> |
