The PCS28-12D-240A-40R is a dual-channel solid state relay (SSR) from CIT Relay & Switch — designed for reliable, silent AC load switching in industrial, automation, and electronics applications. No moving parts means no mechanical wear, no contact bounce, and a far longer service life than electromechanical relays.
Specifications
| Model | PCS28-12D-240A-40R |
| Type | Dual Solid State Relay (SSR) |
| Channels | 2 (independent) |
| Control Input Voltage | 12V DC |
| Load Voltage | 240V AC |
| Resistance | 40Ω |
| Mounting | PCB / panel mount |
| Manufacturer | CIT Relay & Switch |
Solid state vs mechanical relay: Solid state relays use semiconductor switching (no moving contacts), resulting in silent operation, faster switching speeds, no contact arcing, and a significantly longer lifespan. The tradeoff is a small voltage drop across the output and the need for heat management at higher currents.
Common Uses
Industrial automation & process control
HVAC & temperature control systems
Arduino & PLC-controlled AC load switching
Motor & pump control circuits
Lighting control systems
Dual-channel switching from a single component
Common Questions
Can I control this with an Arduino or Raspberry Pi?
Yes — the 12V DC control input is compatible with microcontrollers and PLCs. If driving from a 3.3V or 5V GPIO pin directly, you'll need a transistor or driver circuit to provide the 12V switching signal. Alternatively, use a 12V relay driver module between the microcontroller and this SSR.
Do I need a heatsink?
At low currents the relay runs cool, but under sustained or high load the semiconductor junction generates heat. For continuous duty at higher loads, mounting on a heatsink or providing adequate airflow is strongly recommended to prevent thermal shutdown or damage.
⚠️ Mains voltage warning: This relay switches 240V AC mains voltage. All mains wiring must be performed by a qualified electrician in accordance with local electrical regulations. Datasheet: Download PCS28 Series PDF (CIT Relay & Switch)