A21CSP24VDC1.6D

Relay Automotive Overview

The A21CSP24VDC1.6D is an automotive relay manufactured by CIT Relay and Switch, designed for high-current switching applications in vehicle electrical systems. It features a Single Pole Double Throw (SPDT) contact arrangement with a built-in suppression diode to protect the control circuit from voltage spikes during coil de-energization. The unit operates on a 24VDC coil voltage with a rated current of 1.6A, providing a coil resistance of approximately 90 ohms. The contacts are rated for up to 40A at 14VDC, supporting a maximum switching power of 630W and voltage of 75VDC. Constructed with AgSnO2 contact material, it ensures low initial contact resistance below 30 milliohms. The physical dimensions are 26.0 x 26.0 x 24.5 mm, allowing for compact integration into automotive harnesses.

Relay Automotive Feature Summary

• Integrated suppression diode for reliable coil protection
• High current capacity up to 40A for heavy loads
• Dual mounting options including PCB pins and quick connect terminals

Relay Automotive Applications

• Automotive lighting circuits
• Heater and fan motor control
• Auxiliary power distribution in vehicles

Relay Automotive Procurement Notes

Verify that the specific suffix 'D' confirms the inclusion of the internal flyback diode, as this variant differs electrically from non-diode versions like the 'R' or standard suffixes. Ensure the 24VDC coil rating matches the vehicle's electrical system architecture. Confirm that the SPDT configuration aligns with the required switching logic for the target application. Cross-reference the pinout diagram with the PCB footprint or connector specifications to guarantee mechanical compatibility before finalizing procurement orders.

Relay Automotive Selection Notes

Select this component when a 24VDC control signal is available and a normally open/closed switching capability is required for loads up to 40A. The integrated diode simplifies driver circuit design by eliminating external snubber components. Consider the quick-connect terminal style if rapid assembly or field replacement is prioritized over permanent soldering. Evaluate the thermal performance requirements, as the 630W switching capacity supports significant power dissipation in continuous duty cycles within automotive environments.

Relay Automotive Part Context

This model belongs to the A21 series of automotive relays from CIT Relay and Switch, characterized by a standardized 26x26mm form factor. The series is widely used in global automotive manufacturing due to its robustness and compliance with QS-9000 and ISO-9002 standards. The A21CSP designation indicates a sealed, SPDT configuration suitable for harsh under-hood conditions. Variants within the series differ primarily by coil voltage and the presence of suppression diodes, allowing for flexible integration across various vehicle platforms.

Relay Automotive Replacement Considerations

• A21CSQ24VDC1.6D
• A21CSP24VDC1.9R

Relay Automotive FAQ

What is the function of the 'D' suffix in the part number?

The 'D' suffix indicates that the relay includes an integrated suppression diode connected across the coil terminals to absorb back EMF.

Is this relay suitable for AC applications?

No, the A21CSP24VDC1.6D is specified for DC operation with a 24VDC coil and 75VDC maximum switching voltage rating.