Unison PCB-Mount Solid State Relays: 802 and 806 for OEM Controllers
When the relay belongs on the circuit board, not on the DIN rail.
Machine builders and controller makers often need to switch a solenoid, lamp, small heater or DC motor directly from their own electronics. Unison’s PCB-mounted relays solder onto the board like any component, with optical isolation between the logic side and the load. We stock the 806 RDD 100 05 01 DC-to-DC relay and the slim 802 ZDA 33 06 00 AC relay.
802 and 806 Side by Side
| Feature | 806 RDD 100 05 01 | 802 ZDA 33 06 00 |
|---|---|---|
| Output type | DC (switches DC loads) | AC, zero-cross |
| Code meaning | R = random, D = DC input, D = DC output, 100 = 100 VDC, 05 = 5 A | Z = zero-cross, D = DC input, A = AC output, 06 = 6 A class |
| Typical loads | Solenoid valves, DC motors, lamps, brakes | Small heaters, AC coils, indicator lamps, fans |
| Mounting | Through-hole PCB | Slim module format |
| Why choose it | Fast, silent DC switching with no arcing | Low-noise AC switching at zero volts |
Ratings as printed on the relay label. Confirm input voltage and pin-out with the Unison datasheet before PCB layout.
Other Unison PCB Models
703 / 704
Compact DC-to-AC and DC-to-DC board relays for low-current outputs.
802 / 806
The slim and PCB relays we stock — AC and DC output respectively.
807
Panel-mounted MOSFET DC-to-DC relay for higher DC currents.
Need a model we do not stock? Send us the code — we source directly from Unison.
Unison PCB Relays in Stock
Designing the Board Around a PCB SSR
- Size the copper. Use wide tracks or copper pours on the load side — 5 A needs far more copper than a signal track.
- Keep creepage. Maintain clear spacing between the low-voltage input pins and the load pins; route mains away from logic.
- Add a flyback diode for DC coils. Solenoids and relays kick back when switched off. A diode (or TVS) across the coil protects the 806.
- Fuse every output. Put a fuse in series with each load so a short does not destroy the relay or the board.
- Think about heat. Even small SSRs warm up. Keep them away from electrolytic capacitors and allow airflow.
Unison PCB SSR FAQs
Can a DC-output SSR switch AC?
No. A DC relay like the 806 RDD uses transistors that only switch DC. For AC loads use an AC-output relay such as the 802 ZDA.
What does RDD mean in 806 RDD 100 05 01?
R is random (instant) switching, the first D is a DC control input and the second D is a DC output. 100 is the 100 VDC load rating and 05 is 5 A.
Why choose an SSR over a mechanical PCB relay?
No contact bounce, no sparking and millions more operations — ideal where an output switches frequently.
Does a PCB SSR need a heat sink?
At a few amps usually not, but check the datasheet derating and give it air space on the board.
Can I drive it straight from a microcontroller?
Usually yes, through a small transistor if the input current exceeds what the pin can supply. Check the input current on the datasheet.
Do you supply OEM quantities?
Yes. We quote OEM and repeat-order pricing with GST invoice and scheduled deliveries.
Source Unison PCB Relays
Share the load (AC or DC), voltage, current, control signal and quantity. We will match the right Unison PCB relay and quote OEM pricing.
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