This Product Selection Guide contains information to help select products in the Solid State Relays category on DigiKey.com
Solid-state relays (SSRs) are optically isolated electronic switching devices that switch on or off when a small voltage is applied across control input terminals. SSRs are similar to chassis, DIN rail, socket and board mount electromechanical relays designed to switch either AC or DC loads up to 660 volts but are semiconductor-based and have no moving parts. They are selected by load voltage, current ratings, and switch circuit configurations such as SPST, SPDT, DPST, and 3PST.
SelectionCharacteristics
Mounting Type: Indicates how the device is attached.
Circuit: Describes the contact closures provided by a relay or relay-output device, in terms of the number of independent circuits that are actuated in parallel, the number of contact positions available for each, and their default states. For more information please see Basics of Switches and Relays: An Overview of Poles and Throws
Output Type: Specifies if the relay is designed for AC or DC outputs, along with special performance characteristics.
Voltage - Input: Typically represented by a range, this indicates the low and high voltage limits that one can expect in standard operation. Voltages outside this range may damage the device and other system components.
Voltage - Load: Typically given in a range it represents the low and high voltage limits for the load side- within this range, a device will meet its given specifications. Voltages outside this range may damage the device and other system components.
Load Current: Manufacturer’s indicated peak/absolute maximum continuous load current. Allowable values in practice are subject to de-rating based on application constraints.
On-State Resistance (Max): Characterizes the maximum resistance of a controlled/switched current path through a device when that path is closed, connected, or “on.” Measured under manufacturer-defined test conditions.
Termination Style: Selection of termination style used to connect the device to a system, such as PC pins, stud, or wire leads.
Package / Case: Indicates the type of protective case used on an electronic component to allow easy handling, installation, and protection. This selection was determined to be the closest industry standard applicable to the supplier’s device packaging. Typically it is best to check the actual dimensions from the datasheet rather than depend on this terminology when designing your circuit.
Supplier Device Package: This is what the manufacturer calls the package of this device. They are manufacturer specific. It is typically best to use the actual dimensions from the datasheets rather than to go by this terminology when designing your circuit.
ProductExamples
| MFR PART # | LH1510AT |
|---|---|
| DIGIKEY PART # | LH1510AT-ND |
| MANUFACTURER | Vishay Semiconductor Opto Division |
| DESCRIPTION | Solid State SPST-NO (1 Form A) 6-DIP (0.300", 7.62mm) |
| DATASHEET | Click Here |
| MFR PART # | TLP3403(TP,F |
|---|---|
| DIGIKEY PART # | TLP3403(TPFTR-ND |
| MANUFACTURER | Toshiba Semiconductor and Storage |
| DESCRIPTION | SSR RELAY SPST-NO 100MA 5-48V |
| DATASHEET | Click Here |
| MFR PART # | 8950720000 |
|---|---|
| DIGIKEY PART # | 281-3332-ND |
| MANUFACTURER | Weidmüller |
| DESCRIPTION | SSR RELAY SPST-NO 100MA 5-48V |
| DATASHEET | Click Here |
| MFR PART # | AQY282SX |
|---|---|
| DIGIKEY PART # | 255-AQY282SXTR-ND |
| MANUFACTURER | Panasonic Electric Works |
| DESCRIPTION | RELAY GEN PURPOS DPDT 1A 26.5VDC |
| DATASHEET | Click Here |
SchematicSymbol
Schematic symbol courtesy of Scheme-it. Please see their website for more information and symbols.
MediaLinks
Videos
Relay Basics - Another Teaching Moment | DigiKey Electronics | DigiKey
How to Choose a Relay - Another Teaching Moment | DigiKey
Product Training Modules
PhotoMOS Relays - Panasonic | DigiKey
TechForum