| 摘要 |
1534524 Battery testing EASTMAN KODAK CO 19 Dec 1975 [24 Dec 1974] 52070/75 Heading G1U The voltage across a battery 3 under test is monitored 10, 11, 12, by depressing a key A and a timing circuit 2, 13, 4, ensures that a load 5, 6, 14, which is applied across the battery when the key A is depressed, is removed a fixed (but adjustable 13) time after the key is depressed unless the key is released before this time expires. When the key A is depressed a Schmitt trigger 4 immediately assumes its off state and renders a transistor 5 conductive, thereby applying a load 6, 14 - which simulates a real load - across the battery. The on-load battery voltage is then compared 11 with a Zener 10 reference voltage, and if the battery voltage is sufficiently high a lamp 12 is not lit. If the battery voltage is too low however, the lamp 12 is lit. While the key A is held depressed a capacitor 2 charges, via a resistor 13, and eventually the Schmitt trigger 4 will turn on and remove the load 6, 14 whereupon the lamp 12 will light. A non-electric timer (e.g. pneumatic) could be used, and the circuit is said to be particularly useful in the field of photography. |
