2N4949

Overview

The Central Semiconductor Corp 2N4949 is a Programmable Unijunction Transistor (PUT) designed for through-hole mounting. It functions as a silicon-controlled rectifier equivalent, offering precise voltage triggering characteristics suitable for timing and oscillator circuits. The device features a robust TO-126 or similar axial leaded package configuration, ensuring reliable performance in industrial applications. Key electrical parameters include a peak point voltage typically around 3V, with specific gate trigger levels defined by the manufacturer's datasheet. It operates within standard commercial temperature ranges and provides stable switching behavior for pulse generation tasks.

Feature Summary

• Functions as a programmable unijunction transistor with adjustable gate voltage control
• Provides stable switching characteristics for timing and oscillator applications
• Utilizes through-hole packaging for secure board mounting

Applications

• Timing circuits requiring precise delay intervals
• Oscillator designs for pulse generation
• Triggering stages in thyristor-based power control systems

Procurement Notes

Verify the exact package outline dimensions against your PCB footprint before ordering, as historical revisions may vary slightly. Confirm RoHS compliance status directly with the manufacturer, as older stock may differ from current production runs. Ensure that the gate voltage requirements of your circuit align with the specific PUT characteristics provided in the official datasheet to prevent malfunction.

Selection Notes

Select this component when a discrete PUT solution is preferred over integrated timer ICs for custom voltage thresholds. Consider the thermal dissipation capabilities if operating in high-current environments. Compare the peak point voltage specifications against alternative PUT models to ensure compatibility with existing bias networks. Verify that the through-hole form factor meets the mechanical constraints of the target assembly process.

Part Context

The 2N4949 belongs to the family of programmable unijunction transistors manufactured by Central Semiconductor Corp. These devices serve as versatile alternatives to traditional UJTs, allowing for customizable triggering voltages via the gate terminal. The part is commonly used in legacy and modern electronics where discrete semiconductor switching is required for signal conditioning or power management tasks.

Replacement Considerations

Direct substitutes include other PUT devices such as the 2N6027 or 2N6028, provided the peak voltage and current ratings are compatible. Cross-reference the pinout configuration carefully, as some equivalents may have different anode-cathode-gate arrangements. Always validate electrical parameters against the original design requirements before swapping components.