Abstract: An automatic color-temperature compensation device for television cameras, comprising three filters adapted to pass color rays of the three primary colors, or red, green and blue rays of light from the surroundings, three sensors respectively adapted to detect the red, green and blue rays and to produce an electric signal in response to the detected red, green and blue rays respectively; three log amplifiers for amplifying respective electrical signals; two ratio circuit devices each adapted to compare two of the three electrical signals and produce a ratio output in response to the ratio difference of the two compared electrical signals; two anti-log amplifiers to respectively amplify the two ratio outputs; two comparators for respectively comparing the two amplified ratio outputs with two reference voltages which are so selected as to be equal to the respective ratio outputs at a predetermined color temperature, say 3200.degree. K.

Abstract: A timer-controlled speed changing device for electric fans comprising a timing switch operatively connected to a first speed changing circuit and a second speed changing circuit, for changing the speed of an electric fan from a pre-set speed with the first or second speed changing circuit to another pre-set speed with the second or first speed changing circuit after a predetermined time period set by the timing switch.