| 摘要 |
The invention provides a two-terminal flasher device, particularly for flashing automobile lamps, that can replace the thermal devices predominantly currently in use. An electro-mechanical relay is used to flash the lamps, while an electronic circuit controls the flashing rate. The power for operating the relay and the electronic circuit is maintained by means of a capacitor that is charged from the power source (the battery) and then discharged while the power source is not available, the electronic circuit being supplied from the capacitor via a constant voltage source. Preferably the charging of the capacitor is arranged so as to give an "instant-on" type of operation. The lamp current is measured by a voltage measuring means including a resistor formed by part of the copper of the board on which the circuit is mounted, and the temperature coefficient of the circuit is arranged to be as close as possible to that of the copper. Upon detection of a lamp failure the flashing rate is doubled by by-passing a divider in a timing chain of the circuit. The current supplied to the relay coil is controlled so that a relatively high closing current is supplied initially to close the relay contacts; upon closure of the contacts the relay current is lowered to a holding value (e.g. about one fifth of the closing value) reducing the relay power consumption and capacity required for the capacitor.
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