HJ4-AC12V Equivalent & Substitute Parts

Part Overview

The HJ4-AC12V is a general purpose relay manufactured by Panasonic Electric Works, featuring a 4PDT (4 Form C) contact configuration with a 12VAC coil and 5A contact rating. This socketable relay is designed for standard switching applications requiring multiple independent circuits. The product is currently obsolete, making identification of compatible substitute parts essential for system maintenance, repair, and redesign applications.

Substiute Parts

HJ4-AC12V

Panasonic Electric WorksIn Stock: 1094HJ4-AC12V Datasheet

Current PartRFQ

LY4-AC12

Omron Automation and SafetyIn Stock: 1198LY4-AC12 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the HJ4-AC12V is determined by the following critical parameters:

• Coil Voltage: Must be 12VAC to ensure direct compatibility with existing control circuits
• Contact Form: Must be 4PDT (4 Form C) to maintain the same switching capability and circuit isolation
• Mounting Type: Must be socketable to fit existing relay sockets without mechanical modification
• Termination Style: Must be plug-in to ensure proper electrical connection in socket-based installations
• Coil Type: Must be non-latching to preserve momentary switching behavior

The LY4-AC12 from Omron Automation and Safety meets all critical substitution criteria. While the LY4-AC12 provides a higher contact rating (10A versus 5A), this represents an enhancement rather than a limitation, as it maintains backward compatibility with applications designed for the original 5A specification.

Parameter Comparison

Engineering Selection Recommendations

The LY4-AC12 is the direct functional equivalent for HJ4-AC12V applications. Selection should be based on the following factors:

Product Availability: The HJ4-AC12V is obsolete, while the LY4-AC12 is active and in production. For new designs or system replacements, the LY4-AC12 ensures long-term supply chain continuity.

Compliance Status: The LY4-AC12 carries RoHS Compliant certification, meeting modern environmental and regulatory requirements. This is particularly relevant for applications subject to RoHS directives in manufacturing and distribution.

Performance Enhancement: The LY4-AC12 provides 10A contact rating compared to the original 5A specification. This higher rating does not compromise compatibility with existing 5A-rated circuits and provides additional margin for applications approaching the original current limits.

Electrical Characteristics: Both relays share identical coil voltage, contact form, switching voltage, and operating thresholds. The socketable mounting and plug-in termination ensure mechanical and electrical interchangeability without modification to existing installations.

Frequently Asked Questions (FAQ)

Q: Can the LY4-AC12 be used as a direct replacement in existing HJ4-AC12V sockets?

A: Yes. The LY4-AC12 is mechanically and electrically compatible with HJ4-AC12V sockets. Both relays feature socketable mounting with plug-in termination, allowing direct substitution without socket modification or rewiring.

Q: What is the significance of the higher 10A contact rating on the LY4-AC12?

A: The LY4-AC12 contact rating of 10A exceeds the original 5A specification. This provides additional current-carrying capacity and operational margin. Applications designed for 5A operation remain fully compatible, as the substitute part can handle the original current requirements with additional headroom.

Q: Are the coil operating characteristics identical between the two relays?

A: Yes. Both relays share identical must-operate voltage (9.6 VAC) and must-release voltage (3.6 VAC) specifications. Coil response timing differs slightly (HJ4-AC12V: 20 ms operate/release; LY4-AC12: 25 ms operate/release), but both fall within standard relay response ranges for general purpose applications.

Q: Does the LY4-AC12 meet current regulatory requirements?

A: Yes. The LY4-AC12 is RoHS Compliant, meeting environmental and regulatory standards for electronic components in regulated markets. The obsolete HJ4-AC12V does not carry this certification.

Q: Are there any temperature operating range differences?

A: Yes. The HJ4-AC12V operates from -40°C to 70°C, while the LY4-AC12 operates from -25°C to 40°C. For applications requiring extended low-temperature operation below -25°C, the original specification must be verified against system requirements.

Q: What contact material differences exist between these relays?

A: The HJ4-AC12V uses pure silver (Ag) contacts, while the LY4-AC12 uses silver alloy contacts. Both materials provide reliable switching performance for general purpose applications. Silver alloy contacts offer enhanced durability and resistance to contact wear in high-cycle applications.