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3954_0 AC Solid State Relay 120V 50A, 3954


The 3954_0 AC Solid State Relay can be used to switch loads of up to 50A at 120VAC using the digital output from a Phidget I/O board.

Package includes:

  • A Protective Relay Cover
  • A Heat Transfer Pad
  • An MOV (Metal Oxide Varistor)

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. 

Product Features

  • Connects to a Digital Output
  • Switches mains power AC loads
  • 120 VAC Load
  • 50A Current Rating
  • Connects to any device with a Digital Output


Devices with a Digital Inputs

Product # Name # of Digital Inputs Additional Features
1010 PhidgetInterfaceKit 8/8/8 Mini-Format 8 DIP-36 Package for compact and OEM applications, 8 Analog Inputs, 8 Digital Outputs
1011 PhidgetInterfaceKit 2/2/2 2 Compact USB Dongle Size, 2 Analog Inputs, 2 Digital Outputs
1012 PhidgetInterfaceKit 0/16/16 16 Digital Inputs withstand up to 30V DC, has 16 Open Collector Digital Outputs
1018 PhidgetInterfaceKit 8/8/8 8 8 Analog Inputs, 8 Digital Outputs
1019 PhidgetInterfaceKit 8/8/8 w/6 Port Hub 8 8 Analog Inputs, 8 Digital Outputs, 6-port USB Hub
1047 PhidgetEncoder HighSpeed 4-Input 4 4 Encoder Inputs
1063 PhidgetStepper Bipolar 1-Motor 4 1 Stepper Motor Control
1065 PhidgetMotorControl 1-Motor 2 1 DC Motor Control, 2 Analog Inputs, 1 Encoder Input
1073 PhidgetSBC3 8 Single Board Computer, 8 Analog Inputs, 8 Digital Outputs, 6-port USB Hub
1203 PhidgetTextLCD 8 LCD Character Screen, 8 Analog Inputs, 8 Digital Outputs
Electrical Properties
Relay Output Type SCR
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) 120 V AC
Load Current Min 100 mA
Load Current Max (DC) 10 A
Load Current Max (With 3955 Heatsink) 20 A
Load Current Max (With 3956 Heatsink) 50 A
Load Surge Current 800 A
Turn-on Time Max 1 ms
Turn-off Time Max 11.6 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 HFS34/D-240A80PS-Y