Adapter for low pressure discharge lamps has bridge circuit outputs connected to primary coil winding and to first secondary coil, second output or negative pole to second secondary coil

摘要

The adapter applies a pre-heating frequency to the lamp's heater electrodes at switch-on, then an ignition frequency and then an operating frequency. It contains a frequency-controlled semiconducting bridge circuit (6) followed by the primary coil (L1/1) of a transformer. The contacts of both heater electrodes are driven by two separate secondary coils. A first bridge circuit output (7) is connected to one end of the primary coil winding and via this to the first secondary coil (L1/2) and a second bridge output (8) or the negative pole is connected to the second secondary coil (L1/3) or vice-versa.