| Full Form | Diode for Alternating Current | Triode for Alternating Current |
| Type of Device | Bidirectional Trigger Device | Bidirectional Thyristor/Switch |
| Number of Terminals | 2 (MT1, MT2) | 3 (MT1, MT2, Gate) |
| Layers | 3 or 5 Layers | 5 Layers |
| Junctions | Usually 3 Junctions | 4 Junctions |
| Control Terminal | No Gate | Has Gate Terminal |
| Triggering Method | Breakover Voltage | Gate Current or Breakover Voltage |
| Conducts Current | Both Directions | Both Directions |
| Switching Capability | Cannot control power directly | Can control AC power |
| Power Handling | Low | High |
| Current Rating | Small | Large |
| Voltage Rating | Low to Medium | Medium to High |
| Main Function | Triggering Device | Power Control Device |
| Latching Action | No significant latching | Exhibits Latching & Holding Current |
| Turn ON | At Breakover Voltage | By Gate Pulse |
| Turn OFF | When Current Falls Below Holding Current | When Current Falls Below Holding Current |
| Gate Terminal | Not Available | Available |
| Trigger Sensitivity | Fixed by Breakover Voltage | Adjustable through Gate |
| Symmetry | Highly Symmetrical | Nearly Symmetrical |
| Application | Triggering TRIAC | AC Power Control |
| Cost | Low | Higher than DIAC |