| 摘要 |
The warning device is arranged to be used in conjunction with an instrument gauge on a vehicle fascia. An electrical signal from the instrument gauge, such as a fuel gauge, is fed to the warning device and compared with a reference electrical signal. When the former reaches the latter, the operational amplifier OA1 switches on transistor T1 and a warning lamp lights up. The reference signal is provided by potential divider R4, R5. For use with a gauge, such as a bimetallic strip gauge, whose input is derived from stabilised voltage supply, an alternative form of circuit is used for the warning device where potential divider R4, R5 is fed from the stabilised voltage supply. The warning device could be used to signal high temperature levels, extreme battery voltages or low oil pressure.
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