MRPR-8-37-43 Equivalent & Substitute Parts

Part Overview

The MRPR-8-37-43 is a glass body reed switch manufactured by Littelfuse Inc., configured as a SPST-NO (Single Pole Single Throw - Normally Open) device. This through-hole component is rated for 700mA AC / 1A DC switching at 265V AC and 250V DC, with a 50W power rating. The part operates within a 37–43AT magnetic operate range and is currently classified as obsolete. Due to its obsolete status, identifying functionally equivalent substitute components is essential for design continuity and procurement planning.

Substiute Parts

MRPR-8-37-43

Littelfuse Inc.In Stock: 929MRPR-8-37-43 Datasheet

Current PartRFQ

MRPR-20-22-28

Littelfuse Inc.In Stock: 1944MRPR-20-22-28 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The MRPR-20-22-28 qualifies as a direct substitute based on the following alignment of critical electrical and mechanical parameters:

Substitution Criteria:

• Circuit configuration: Both SPST-NO
• Voltage rating: Both 265V AC / 250V DC
• Power rating: Both 50W
• Mounting type: Both through-hole axial termination
• Physical dimensions: Identical body size (0.112" Dia × 0.800" L) and overall length (2.230")
• Operating temperature range: Identical (-20°C to 125°C)
• Switching time characteristics: Identical operate and release times (0.75ms / 0.3ms)
• Capacitance: Identical (0.2 pF)
• RoHS compliance: Both ROHS3 compliant

Differentiation: The MRPR-20-22-28 operates within a lower magnetic operate range (22–28AT) compared to the MRPR-8-37-43 (37–43AT), and provides higher switching current ratings (1.1A AC / 1.5A DC versus 700mA AC / 1A DC). The substitute part is currently in active production status.

Parameter Comparison

Engineering Selection Recommendations

The MRPR-20-22-28 is the direct substitute for the obsolete MRPR-8-37-43. Both components maintain identical electrical voltage ratings, power handling, and physical form factors. The substitute part is currently in active production status, ensuring long-term availability and supply chain continuity.

The MRPR-20-22-28 exhibits higher switching current capacity (1.1A AC / 1.5A DC versus 700mA AC / 1A DC) and a lower magnetic operate range (22–28AT versus 37–43AT). These differences must be evaluated against application-specific requirements. If the original design depends on the higher magnetic operate threshold of the MRPR-8-37-43, the substitute's lower operate range may result in unintended activation at lower magnetic field strengths.

Both components are ROHS3 compliant and carry identical regulatory classifications (EAR99, HTSUS 8536.50.9065), supporting regulatory and compliance requirements without modification.

Frequently Asked Questions (FAQ)

Q: Can the MRPR-20-22-28 directly replace the MRPR-8-37-43 in all applications?

A: The MRPR-20-22-28 is mechanically and electrically compatible in terms of mounting, termination, voltage rating, and power handling. However, the operate range differs: the substitute activates at a lower magnetic field strength (22–28AT versus 37–43AT). Applications requiring the higher operate threshold of the original part must be re-evaluated.

Q: What is the significance of the operate range difference?

A: The operate range specifies the magnetic field strength (in Ampere-Turns) required to close the reed switch contacts. The MRPR-8-37-43 requires 37–43AT, while the MRPR-20-22-28 requires 22–28AT. In applications using electromagnets or permanent magnets to activate the switch, this difference affects the required magnetic field intensity.

Q: Are there any compliance or certification differences?

A: Both parts are ROHS3 compliant and carry identical regulatory classifications. No compliance barriers exist for substitution from a regulatory standpoint.

Q: What is the packaging difference?

A: The MRPR-8-37-43 is listed with standard through-hole packaging. The MRPR-20-22-28 is supplied in bulk packaging. Verify bulk packaging specifications against procurement and handling requirements.

Q: Can I use the MRPR-20-22-28 if my application requires higher switching current?

A: Yes. The MRPR-20-22-28 provides higher switching current ratings (1.1A AC / 1.5A DC versus 700mA AC / 1A DC), making it suitable for applications requiring increased current handling. The higher current capacity does not create compatibility issues in designs originally specified for lower current.