Solid-state relay (SSR-25DA)
Fotek-style SSR-25DA · input 3–32 V DC (about 7.5 mA) · output 24–380 V AC, 25 A with a heatsink · opto-TRIAC inside with zero-cross switching · about 1.2 V drop and a few mA of snubber leakage when off
Try it on the benchThe lab drops it on an empty bench and opens its datasheet card.
Typical part: Fotek SSR-25DA style solid-state relay
Pins
- 1 Load (AC)
- 2 Line (AC)
- 3 + input
- 4 − input
Ratings and limits
| Input | 3–32 V DC, ≈ 7.5 mA |
|---|---|
| Output | 24–380 V AC |
| Current | 25 A with heatsink, about a third without |
| Drop | ≈ 1.2 V (≈ 1.2 W per amp of heat) |
How to use it
No moving contacts, no click, switches at the zero crossing so there is no inrush spark. AC only: an AC SSR never turns off on DC. Cheap ones are often under-rated: derate by half and use a heatsink.