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Top » Catalog » Controllers » Relays » 3950_0 » DC Solid State Relay - 30V 50A [3950_0]

This SSR switches up to 30VDC/50A and connects to a PhidgetInterfaceKit 0/16/16.

DC Solid State Relay - 30V 50A

This SSR switches up to 30VDC/50A and connects to a PhidgetInterfaceKit 0/16/16.

The 3950 DC Solid State Relay can be used to switch loads of up to 50A at 30VDC using the digital output from a 1012 - PhidgetInterfaceKit 0/16/16. The Relay comes with an optional protective cover to protect people from touching the exposed high power wires, and a diode to protect your SSR from harmful transients. All wires connect to this relay by screw terminals. If you are switching a high power load or find the relay is getting hot, please consider a heat sink. Heat sinks 3955 and 3956 are designed for use with this relay.

Comes Packaged with:

  • A Protective Relay Cover

  • A Heat Transfer Pad

  • A Diode

  • Electrical Properties

    Relay Output Type MOSFET
    Isolation Method Photoelectric
    Dielectric Strength 2.5 kV AC
    Control Voltage Min 3 V DC
    Control Voltage Max 32 V DC
    Load Voltage Max (DC) 30 V DC
    Load Current Min 20 mA
    Load Current Max (DC) 18 A
    Load Current Max (With 3955 Heatsink) 50 A
    Load Current Max (With 3956 Heatsink) 50 A
    Load Surge Current 120 A
    Turn-on Time Max 1 ms
    Turn-off Time Max 0.5 ms

    Physical Properties

    Length 58 mm
    Width 45 mm
    Height 25 mm
    Operating Temperature Min -30 °C
    Operating Temperature Max 80 °C

    Other Properties

    Manufacturer Part Number HFS33/D-30D50M

    Have a look at the Data Sheet for a complete set of specifications.

    This relay connects to the 1012 - PhidgetInterfaceKit 0/16/16. Just connect the positive control terminal of the SSR to the +5V terminal on the 1012, and connect the negative terminal to an open collector digital output on the 1012.


    You could also buy the male connector, which is a Molex 50-57-9405, and crimp it onto the end of the cable, if you have the appropriate tools.


    1. When choosing a SSR, check the actual load current and the working ambient temperature. Refer to the characteristic curve in the Data Sheet and select the proper heat sink if required.
    2. Use the heat transfer pad between the SSR and the heat sink. Failure to do so can cause overheating and could damage the relay.
    3. Make sure that the SSR terminal screws are tight. If the screws are not tight, the SSR will get damaged by heat generated when the power is ON. Check the Data Sheet for recommended tightened torque.
    4. When an SSR fails, it most often fails permanently closed - leaving your load powered, and possibly creating a fire or safety hazard.
    5. You can use a fuse to protect your circuit from wiring mistakes and accidental short-circuits.
    6. Make sure that you use the relay within the product specifications.

    This product was added to our catalog on Wednesday 08 October, 2014.