摘要 |
During the emission-spectroscopical testing of metallic samples by means of unipolar discharges, material is precipitated onto the counterelectrode material which leads to faulty test results. According to the invention, at the start of the pre-spark period half waves of the unipolar discharge are replaced by oscillating discharges, wherein two parallel-connected discharge capacitors and two series-connected discharge resistors, one discharge capacitor and one discharge resistor can be shunted and the shunting is canceled out after a prespecified period of time, starting with the pre-spark period. |