Difference Between AC and DC Welding:
The Difference between AC and DC welding is given in table below
| Particulars | DC Welding | AC Welding |
| Equipment | Motor-generator set or rectifier is required in case of availability of ac supply, otherwise oil engine-generator set is required. | In case of availability of ac supply only a transformer is required. Transformer costs less and its maintenance cost is also low. |
| Prime cost | Two to three times as compared to that of a transformer. | Comparatively low. |
| Operating efficiency | Low; consequently high cost of electrical energy. | High (about 85%). |
| No-load voltage | Low (safer). | Frequently too high (dangerous). |
| No-load requirements | Very high. | Low (advantageous). |
| Power factor | Comparatively higher. | Low, requiring Capacitors for correction. |
| Arc blow | Pronounced. | Not so pronounced with ac (advantageous). |
| Electrodes | Both bare (non-coated) and thus cheap electrodes can be used. | Only coated electrodes—expensive ones. |
| Heating | Uniform | Not so uniform as in case of dc. |
| Connected load (cross-sectional area of conductors and fuses) | Normal. | Considerably higher because of low power factor. |
| Welding of non-ferrous metals | Suitable. | NA |
| Arc stability | Higher. | NA |