Why Choose the Finder 40.61.7.012.4320 12 V DC 16 A Miniature PCB Relay?
The Finder 40.61.7.012.4320 is a high-performance 12 V DC miniature electromagnetic power relay designed for reliable electrical switching in industrial automation, electronic control systems and printed circuit board assemblies. Part of the Finder 40 Series, this relay combines a 16 A rated contact current, a sensitive DC coil and robust silver-tin oxide contacts in a compact housing.
Featuring a single normally open contact (1NO / SPST-NO), the Finder 40.61.7.012.4320 is designed to close a compatible electrical circuit when its coil is energised. Unlike changeover relays, this particular configuration provides a normally open switching function rather than separate normally open and normally closed outputs.
Its 500 mW sensitive DC coil offers efficient operation from a suitable 12 V DC control supply. The silver-tin oxide (AgSnO₂) contact material provides robust switching characteristics, particularly valuable where electrical loads can produce elevated inrush currents.
With a compact body measuring approximately 29 × 12.4 × 25 mm, the Finder 40.61.7.012.4320 is an excellent solution for equipment manufacturers, PCB designers and automation engineers requiring dependable high-current switching from a low-voltage control circuit.
Key Advantages
- 16 A rated switching current for compatible resistive electrical loads.
- 12 V DC sensitive coil for low-voltage control applications.
- Single normally open contact (1NO / SPST-NO) for straightforward load switching.
- 500 mW nominal coil consumption reduces control power requirements.
- Silver-tin oxide (AgSnO₂) contacts provide robust switching performance.
- High inrush-current capability under the manufacturer's specified conditions.
- Monostable operation automatically opens the contact when coil power is removed.
- Compact PCB mounting design saves space in electronic equipment.
- 288 Ω nominal coil resistance supports predictable control circuit design.
- Approximately 42 mA nominal coil current for efficient electronic interfacing.
- Reinforced coil-to-contact insulation supports separation between control and load circuits.
- 6 kV impulse withstand capability between coil and contacts.
- Wide −40 to +85 °C operating temperature range.
- Compact 29 mm housing length for space-conscious PCB layouts.
- Finder 40 Series construction for professional electronic switching applications.
Key Features
- Finder 40 Series miniature power relay.
- Manufacturer part number 40.61.7.012.4320.
- 12 V DC nominal coil voltage.
- Sensitive DC coil configuration.
- 500 mW nominal coil power.
- 288 Ω nominal coil resistance.
- Approximately 41.7 mA calculated coil current.
- One normally open contact.
- SPST-NO switching configuration.
- 16 A rated resistive contact current.
- 250 V AC rated contact voltage.
- Silver-tin oxide contact material.
- Monostable, non-latching operation.
- Through-hole PCB mounting.
- Compact miniature relay housing.
- Approximately 29 × 12.4 × 25 mm dimensions.
- −40 to +85 °C operating temperature range.
- Reinforced coil-to-contact insulation within the Finder 40 Series design.
- 6 kV coil-to-contact impulse withstand rating.
- 8 mm coil-to-contact creepage and clearance design.
How the Finder 40.61.7.012.4320 Relay Works
The Finder 40.61.7.012.4320 operates using a sensitive electromagnetic coil and a single normally open contact. This arrangement allows a compatible 12 V DC control circuit to switch a separate electrical load without requiring the control electronics to carry the load current directly.
When the relay coil is de-energised, the normally open contact remains open and the connected load circuit is interrupted. Applying the correct 12 V DC control voltage energises the coil, creating a magnetic field that moves the relay armature and closes the contact.
Once the contact closes, current can flow through the connected load circuit, provided the load remains within the relay's specified electrical ratings. Removing the coil voltage causes the relay to return to its normal position, reopening the contact.
This monostable switching behaviour makes the relay useful for equipment that should return to an electrically open output state when its control supply is removed. Unlike a bistable or latching relay, the Finder 40.61.7.012.4320 does not retain its energised contact position without coil power.
The relay's 500 mW sensitive coil has a nominal resistance of 288 Ω. At 12 V DC, this corresponds to a calculated nominal current of approximately 41.7 mA.
Although the coil requires relatively little power, the controlling circuit must still be capable of supplying the necessary current. Many microcontroller output pins cannot drive this coil directly, so a suitable transistor, MOSFET or dedicated relay driver is generally recommended.
When using a semiconductor driver, an appropriately selected flyback diode or alternative transient suppression circuit should be considered to protect the control electronics from the inductive voltage generated when the coil is switched off.
16 A Switching Performance and AgSnO₂ Contacts
The Finder 40.61.7.012.4320 features a 16 A rated normally open contact with silver-tin oxide (AgSnO₂) contact material. This combination is suitable for switching compatible electrical loads in industrial and electronic control applications.
Silver-tin oxide is valued for its resistance to contact welding and its performance under demanding switching conditions. This makes it useful in applications where the load may produce a significant initial current surge when switched on.
The Finder 40.61 family specifies a 4,000 VA AC-1 resistive switching capacity. However, the maximum permissible load depends on the type of equipment being switched, the supply voltage, the switching frequency and the expected electrical endurance.
For the AgSnO₂ version of the 40.61 relay, Finder identifies a short-duration peak-current capability of up to 120 A for 5 ms on the normally open contact. This is a peak switching characteristic, not a continuous current rating, and must be applied only within the manufacturer's specified conditions.
LED drivers, switch-mode power supplies, transformers and other capacitive or inductive loads may draw substantially more current at switch-on than during normal operation. The relevant load characteristics and Finder switching guidance must therefore be checked before selecting the relay.
PCB Mounting and Electrical Integration
The Finder 40.61.7.012.4320 is designed for direct through-hole PCB mounting. Its compact body dimensions of approximately 29 × 12.4 × 25 mm make it suitable for electronic control boards and equipment where space is limited.
PCB designers should follow the manufacturer's recommended terminal layout and provide appropriate copper track widths, conductor spacing, creepage distances and thermal management for the intended electrical load.
The Finder 40.61 family features reinforced coil-to-contact insulation, with a 6 kV impulse withstand rating and an 8 mm creepage and clearance design. These characteristics support electrical separation between the control circuit and the switched load when the relay is incorporated into a correctly designed assembly.
Because the 40.61.7.012.4320 is a normally open variant, its contact configuration and terminal arrangement should be checked carefully before replacing another 40.61 relay. A relay with a changeover contact may not be a direct replacement even if the coil voltage and rated current are identical.
The complete electronic assembly must include suitable protection against overcurrent, overheating, accidental contact and electrical faults. The relay's individual electrical ratings do not replace the need for appropriate system-level design.
Typical Applications
- Industrial electronic control boards.
- Embedded controller output switching.
- 12 V DC control systems.
- PCB-mounted electrical load switching.
- Industrial automation equipment.
- Electronic power management circuits.
- Building automation control electronics.
- Control of compatible LED drivers and lighting loads.
- Electronic equipment requiring normally open switching.
- Machine control and auxiliary switching circuits.
- Remote equipment control systems.
- Electrical monitoring and alarm equipment.
- Electronic power supply switching assemblies.
- Professional PCB manufacturing and equipment integration.
- Repair and maintenance of compatible industrial electronics.
