Q4008F42

Triacs Overview

The Littelfuse Q4008F42 is a bidirectional triac designed for AC power control applications. It features an RMS on-state current of 8 A and a rated repetitive peak off-state voltage of 400 V. The device operates within a temperature range of -40°C to +125°C and utilizes a TO-202-3 (TO-92) through-hole package. Key electrical characteristics include a maximum holding current of 50 mA, a gate trigger voltage of 2.5 V, and a gate trigger current ranging from 25 mA to 50 mA. The on-state voltage is specified at 1.6 V, with non-repetitive peak currents of 83 A and 100 A.

Triacs Feature Summary

• Bidirectional switching capability for alternating current circuits
• Through-hole mounting in a compact TO-202-3 package
• High thermal stability operating up to 125°C

Triacs Applications

• AC motor speed control systems
• Solid-state relay output stages
• Lighting dimmer circuits

Triacs Procurement Notes

Verify component authenticity by checking manufacturer markings against official datasheet specifications. Confirm the specific suffix matches the required pinout and electrical tolerances. Note that availability may be limited as this part number is listed as obsolete or discontinued by major distributors. Source only from authorized channels to ensure reliability.

Triacs Selection Notes

Select this component when a low-current 400V triac is required for through-hole assembly. Ensure the gate drive circuit can supply the necessary 25-50 mA trigger current. Verify that the load current does not exceed the 8 A RMS rating under expected thermal conditions. Consider the TO-202-3 package size constraints during PCB layout design.

Triacs Part Context

This device belongs to the Littelfuse Qxx08F series of general-purpose triacs. The series provides standardized performance for basic AC switching tasks. The F42 suffix indicates the specific packaging and terminal configuration compatible with standard through-hole printing processes.

Triacs Replacement Considerations

Direct substitutes include other 8A/400V triacs in TO-202 packages such as the BT137 or BTA16 variants, provided pinouts are verified. Cross-reference gate sensitivity requirements carefully before substitution.