| 摘要 |
The disclosed circuit intended to operate gas discharge lamps is designed so that in the case of failure, the oscillating circuit of the protection circuit is considerably weakened in order to avoid an overvoltage, yet without disconnecting completely the protection circuit and, as a result, once the failure has been repaired, the protection circuit may start again by itself. As a function of the voltage increase, a reactance coil (DR) is connected to the control circuit of the electronic switches (S2) of the inverter circuit via a thyristor (12) which is controlled by the voltage increase and which effects said weakening if the thyristor (12) is energized, said switching state being maintained up to the elimination of the failure cause. The hypostatic current required by the thyristor (12) to maintain said state may be tapped either on the control circuit of the electronic switch (S2) or also from another voltage source of the protection circuit, while nevertheless making sure that said hypostatic current is available, preferably without losses, in case of need. |
