| 摘要 |
To provide a reliable start for cadmium and zinc lamps and reduce baseline noise in an absorbance monitor, voltage pulses are applied to the primary of a transformer followed by shutoff of the primary current which discharges the energy stored in the magnetizing inductance of the transformer as three thousand volt peaks in its secondary in a series of timed steps. At the end of the timed period, the system shuts down unless it has approached operating frequency. The frequency is controlled by the amount of current passing through a gas discharge lamp in circuit with the transformer secondary and the frequency controls the amplitude of the voltage spikes. After warm-up, blanking pulses prevent optical noise from electrical-path-change oscillations within the tube. In one embodiment, a constant current source controls the current and in another, an operating current and frequency are established by the transformer leakage inductance and lamp characteristics in the circuit. |
