What Is the SRD-05VDC-SL-C? 5V Relay: Wiring and Uses
The SRD-05VDC-SL-C (Songle) is a 5 V coil SPDT electromechanical relay; the standard relay of Arduino/relay modules. With a small control signal it switches ~10 A @ 250 VAC (contacts COM/NO/NC). An MCU cannot drive the coil directly → a transistor (2N2222/BC547/ULN2003) + flyback diode (1N4007) are needed (on the module they are on the board).
The SRD-05VDC-SL-C (Songle) is a 5 V coil, single-pole double-throw (SPDT / 1 Form C) electromechanical relay. It is the standard relay of Arduino/relay modules; with a small control signal it switches high-voltage/current AC-DC loads. For the concept, see what is a relay.
What is the SRD-05VDC used for?
Turning mains loads such as lamps, motors, pumps and heaters on/off, isolated from an MCU. Contact set: COM (common), NO (normally open), NC (normally closed). When the coil energizes, COM moves from NC to NO.
Watch out: driving the coil + flyback diode
An MCU pin cannot drive the relay coil directly (the coil draws ~70 mA). Put a transistor in between (2N2222/BC547 or ULN2003) and connect a flyback diode (1N4007) across the coil — otherwise the coil's back-EMF destroys the transistor. On ready relay modules these are already on the board.
Specifications
| Parameter | Value |
|---|---|
| Type | Electromechanical relay (SPDT) |
| Coil | 5 V DC (~70 mA) |
| Contact | ~10 A @ 250 VAC / 30 VDC |
Equivalents
- JQC-3F (T73): a common relay of the same class.
- SRD-12VDC-SL-C: the 12 V coil version.
- SSR-25DA: a solid-state relay with no moving parts (AC).
Find it in our catalog
Use the SRD-05VDC search.