| 摘要 |
An alternator circuit comprises an alternator having an armature winding, a field winding, a voltage regulator, a fault detecting circuit, a lamp drive circuit having its input connected to the output of the fault detecting circuit, and a warning lamp driven by the drive circuit. The drive circuit includes a capacitor connected across its input, an input transistor, an output transistor, a current measuring resistor connected in series with the output transistor, and a transistor sensitive to both the voltage drop across the warning lamp and the voltage drop in the current measuring resistor. In the event of excessive current flow through the output transistor, the voltage sensitive transistor rapidly charges the capacitor thereby turning off the output transistor. The capacitor then discharges slowly and the cycle is repeated. The high inrush current in the warning lamp does not cause the capacitor to be charged as the associated voltage drop across the lamp offsets the voltage drop in the current measuring resistor.
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