| 摘要 |
Connected in parallel to the lamp through a fuse (10) is a triac (2) the control electrode of which is connected through a diac (3) to the tap (4) of a voltage divider likewise in parallel with the lamp. The first branch of the voltage divider contains, in addition to a fixed resistor (5), at least one variable series impedance (6) which may be either a capacitor or a voltage-dependent resistor. The second branch of the voltage divider is provided by a capacitor (7). A temperature dependent NTC resistance (8) bridges a portion of the first branch and all of the second branch of the voltage divider. For use with ballasts containing a choke, it is desirable to interpose a diode bridged by a NTC resistor in the first branch of the voltage divider adjacent to the tap. An anti-interference capacitor (9) is connected across the triac and can be replaced by a capacitive voltage divider for use with lamps of higher ignition voltage, in which case one capacitive branch of the capacitive voltage divider is bridged by a self-switching four-layer diode, to which it is possible to add a small series inductor. The starter circuit is suitable for a wide range of operating conditions of the lamp. |
