| 摘要 |
To prevent long-time current flow through a positive temperature coefficient resistor (KL) included in the heater circuit of one or more fluorescent lamps (LP, LP1, LP2), a relay is connected in circuit with the PTC resistor (KL), which will respond when the voltage across the capacitor (C4) reaches the level of d-c voltage derived from a relay rectifier (GL) and coupled to the PTC resistor itself. The relay operates a switch contact (S) which interrupts the current flow through the PTC resistor; the flow through the relay is small in comparison with the current flow through the PTC resistor, thereby saving energy and decrease in the heat loading on the circuit structure.
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