SP-21

Overview

The Triad Magnetics SP-21 is a high-reliability audio and signal transformer designed for demanding applications. It features a primary impedance of 10 kΩ center-tapped and a secondary impedance of 2 kΩ center-tapped, with a turns ratio of approximately 2.24:1. The device operates within a frequency range of 300 Hz to 100 kHz and supports an isolation voltage of 1 kV. Rated power is 50 mW (1/20 W) with a current rating of 1 mA. DC resistance measures 1.05 kΩ on the primary side and 330 Ω on the secondary side. The component adheres to MIL-T-27E standards and utilizes radial through-hole mounting.

Feature Summary

• Complies with MIL-T-27E military specifications for high reliability
• Center-tapped winding configuration on both primary and secondary sides
• Radial leaded construction for through-hole PCB integration

Applications

• High-reliability audio signal processing circuits
• Impedance matching in professional audio equipment
• Military and aerospace electronic systems requiring certified components

Procurement Notes

Verify that the ordered part number matches the exact SP-21 designation without suffix variations unless explicitly documented as functionally identical. Confirm compliance with MIL-T-27E requirements if the application mandates military-grade standards. Ensure the supplier provides original manufacturer documentation to validate the 1 kV isolation rating and 50 mW power limits. Cross-reference the center-tapped impedance values against schematic requirements before finalizing procurement.

Selection Notes

Select this component when a center-tapped audio transformer with 10 kΩ primary and 2 kΩ secondary impedances is required. The 300 Hz to 100 kHz frequency response suits standard audio band applications. Consider the radial package dimensions and through-hole mounting style for board layout compatibility. The 1 kV isolation voltage provides adequate safety separation for low-power signal applications.

Part Context

The SP-21 belongs to the Triad Magnetics audio and signal transformer product line. It is categorized under general-purpose transformers designed for signal coupling and impedance transformation. The series adheres to specific military performance standards, distinguishing it from commercial-grade alternatives by its rigorous testing and reliability criteria.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Verify pinout and impedance ratios carefully when considering alternative manufacturers.