What Is the SSR-25DA? Solid-State Relay (SSR): Specs and Uses
The SSR-25DA is a solid-state relay (SSR) with no moving parts. With 3–32 V DC control it switches up to 25 A AC (24–380 VAC) silently, without sparks and isolated; it contains an optocoupler + triac. Compared with an electromechanical relay it is silent, wear-free and long-lived, but it produces heat (a heatsink is a must) and has a small leakage current.
The SSR-25DA is a solid-state relay (SSR) with no moving parts. With a low DC control signal (3–32 V) it switches a large AC load (up to 25 A) silently, without sparks and quickly. For the concept, see what is a relay.
What is the SSR-25DA used for?
Heater/temperature control (PID), lighting, motors and frequently switched AC loads. It contains an optocoupler + triac/SCR; input and output are isolated. Compared with an electromechanical relay it is silent, wear-free and far longer-lived.
Connection
Input: DC control (3–32 V, +/−); Output: AC load (e.g. 24–380 VAC, "DA" = DC input, AC output). The "DD" version has a DC output. An MCU pin is usually enough for the input (low current).
Specifications
| Parameter | Value |
|---|---|
| Type | Solid-state relay (DC→AC) |
| Control | 3–32 V DC |
| Load | ~25 A AC (24–380 VAC) |
| Switching | Usually zero-cross, optically isolated |
Watch out
An SSR produces some heat under load → a heatsink is needed (especially at high current). Its leakage current is not zero (a small current can flow even when off). Choose the right version/snubber for inductive loads.
Equivalents
- SSR-40DA: higher current (40 A).
- G3MB-202P: a small PCB-type SSR.
- SRD-05VDC: an electromechanical relay (mechanical contact).
Find it in our catalog
Use the SSR-25DA search.