| 摘要 |
PURPOSE:To attain the automatic changeover between a primary dry cell and a solar battery in accordance with the ambient luminous intensity, by comparing the electromotive voltage levels between the primary dry cell and the solar battery and gives the ON/OFF control to a semiconductor switch in response to said comparison output. CONSTITUTION:In the case of the high luminous intensity, a semiconductor switch means Q1 is adversely biased by a diode D3 and then cut off. While a semiconductor switch means Q2 is biased forward. Thus a primary dry cell Eb is cut off to an arithmetic circuit part 3 and the power is supplied from a solar battery ES. While the means Q2 is adversely biased by a diode D2 and cut off in the case of the low luminous intensity. While the means Q1 is biased forward. Thus the battery ES is cut off to the part 3 and the power is supplied from the cell Eb. |
