AC Spark
Definition and meaning of AC Spark in chemistry.
An AC spark is a high-voltage alternating-current electrical discharge used as an excitation source in atomic emission spectroscopy. The repeated spark vaporizes a small amount of a solid sample and excites its atoms so that they emit light characteristic of the elements present.
In more detail
Because it uses a high voltage that discharges many times per second, an AC spark delivers more energy to the sample than an arc, giving better precision and making it well suited to quantitative analysis of metals and alloys. Each discharge strikes a fresh spot, which improves reproducibility. Spark-source emission spectrometers were long a standard tool in the metals industry, though many analyses have since moved to the inductively coupled plasma (ICP).
Key facts
| Type | High-voltage AC discharge |
|---|---|
| Use | Excitation source in emission spectroscopy |
| Best for | Quantitative analysis of metals and alloys |
| Field | Analytical Chemistry |
A spark struck repeatedly between an electrode and a steel sample lets a spectrometer read the alloy's composition from the emitted light.
Frequently asked questions
How does an AC spark differ from an AC arc?
A spark uses a higher voltage and brief, repeated discharges, giving better precision for quantitative work, while an arc is a lower-voltage, more continuous discharge that is more sensitive but less reproducible.