Why Choose the Finder 77.01.9.024.8050 Solid State Relay?
The Finder 77.01.9.024.8050 is a compact 5 A solid state relay (SSR) designed for reliable, contactless switching of single-phase AC electrical loads. Part of the Finder Series 77 modular solid state relay range, this industrial switching device combines semiconductor technology, a nominal 24 V DC control input and zero-crossing switching in a slim DIN rail mounted housing.
Featuring a 48–265 V AC output switching range and a 5 A rated load current, the Finder 77.01.9.024.8050 is suitable for appropriately rated lighting circuits, heating equipment, solenoid-operated devices and industrial automation applications. Its zero-crossing switching technology activates the output close to the AC voltage zero crossing, helping reduce switching transients and inrush effects in suitable applications.
Unlike a conventional electromechanical relay, the Finder 77.01.9.024.8050 uses a photo-coupled semiconductor switching mechanism without moving power contacts. This provides silent operation and eliminates mechanical contact wear. Its 17.5 mm wide modular housing, screw terminal connections and DIN rail mounting make it a practical solution for electrical control panels, building automation systems and industrial machinery.
Key Advantages
- 5 A solid state relay for dependable single-phase AC load switching.
- 24 V DC nominal control input for industrial automation and electronic control systems.
- 4–32 V DC operating input range provides flexibility for compatible DC control signals.
- 48–265 V AC output range for switching suitable AC electrical loads.
- Zero-crossing switching helps minimise switching disturbances in compatible applications.
- Contactless semiconductor operation eliminates mechanical contact wear.
- Silent switching makes it suitable for noise-sensitive electrical installations.
- 5 kV input-to-output impulse insulation provides electrical separation between control and load circuits under specified test conditions.
- 17.5 mm slimline housing helps conserve space inside electrical cabinets.
- 35 mm DIN rail mounting supports convenient installation in control panels.
- Screw terminal connections provide practical electrical wiring.
- −20 to +70 °C operating temperature range for suitable industrial environments.
- Ideal for lighting control, electric heating, solenoids and automated AC switching.
Key Features
- Finder Series 77 modular solid state relay.
- Single-phase AC output switching.
- Normally open equivalent output: 1 Form A / SPST-NO.
- Nominal control voltage: 24 V DC.
- Control input operating range: 4–32 V DC.
- Rated output current: 5 A.
- Output switching voltage: 48–265 V AC.
- Switching characteristic: Zero crossing.
- Maximum peak current: 300 A for 10 ms under specified conditions.
- Photo-coupled semiconductor switching for contactless operation.
- Input-to-output impulse insulation: 5 kV (1.2/50 µs).
- Modular housing width: 17.5 mm.
- Mounting: DIN rail.
- Terminal type: Screw terminals.
- Operating temperature: −20 to +70 °C.
- Single-pole switching arrangement for suitable AC circuits.
- Silent, mechanically contact-free operation.
Technical Specifications
- Manufacturer: Finder
- Series: 77
- Manufacturer part number: 77.01.9.024.8050
- Product type: Modular solid state relay (SSR)
- Relay technology: Photo-coupled semiconductor
- Switching arrangement: SPST-NO equivalent (1 Form A)
- Number of output poles: 1
- Nominal input voltage: 24 V DC
- Input operating voltage range: 4–32 V DC
- Input supply type: DC
- Output type: AC
- Output voltage range: 48–265 V AC
- Rated output current: 5 A
- Switching method: Zero-crossing turn-on
- Maximum peak current: 300 A for 10 ms
- Input-to-output impulse insulation: 5 kV (1.2/50 µs)
- Housing width: 17.5 mm
- Mounting type: DIN rail mounting
- Connection type: Screw terminals
- Operating temperature: −20 to +70 °C
- Switching operation: Contactless semiconductor switching
- Approvals listed for the product: CE, cULus, EAC and UKCA
- Typical applications: Lighting, heating, solenoids and industrial AC load control
How Zero-Crossing Solid State Switching Improves AC Load Control
The Finder 77.01.9.024.8050 uses semiconductor switching technology to control an AC electrical load from a low-voltage DC input. When a compatible control signal is applied within its 4–32 V DC input range, the relay enables the AC output at the appropriate zero-crossing point. This makes the device particularly useful for applications where controlled switching of AC loads is desirable.
Zero-crossing switching means that the relay turns on when the instantaneous AC voltage is close to zero. For suitable resistive and lighting loads, this can help reduce electrical switching disturbances compared with switching at arbitrary points in the AC waveform. It can also help manage switching transients in selected applications, although actual inrush current depends on the connected load characteristics.
Unlike an electromechanical relay, the Finder 77.01.9.024.8050 does not rely on moving contacts to complete the power circuit. Its solid state switching mechanism enables silent operation without mechanical contact bounce or contact erosion. This makes it useful in automated systems where quiet, repeatable switching is required.
The relay's 5 A rated output and 48–265 V AC switching range make it suitable for appropriately rated single-phase AC loads. The specified 300 A peak current for 10 ms is a short-duration surge capability and must not be confused with the relay's continuous output current rating.
Because solid state relays generate heat during conduction, correct installation and thermal management are important. The actual permissible load current may depend on ambient temperature, mounting conditions and the manufacturer's derating requirements. A solid state relay may also allow a small leakage current when switched off, so it must not be treated as a substitute for a safety-rated isolator or mechanical disconnection device.
The Finder 77.01.9.024.8050 is designed for DIN rail mounting and uses screw terminals for electrical connections. Its slim 17.5 mm housing allows multiple modules to be accommodated within industrial electrical cabinets while supporting straightforward integration into compatible control systems.
Typical Applications
- Single-phase AC electrical load switching.
- Industrial heating element control.
- Electric heaters and temperature control systems.
- Commercial and industrial lighting control.
- Compact fluorescent lighting switching applications.
- Building automation and electrical control systems.
- Industrial machinery and automated equipment.
- Solenoid and contactor coil control within suitable electrical ratings.
- PLC-controlled AC switching through compatible DC outputs.
- Industrial process control and automation panels.
- OEM machinery requiring silent electrical switching.
- DIN rail mounted control cabinet installations.
