Power Transistor BU2508A NPN, 8A TO-247

Power Transistor BU2508A NPN, 8A TO-247

Transistors

Reference: TRBU2508A

Part.No: BU2508A

€3.55

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The BU2508A is a high-voltage NPN power transistor in a TO-247 package, purpose-built as a Line Output Transistor (LOPT) for CRT monitor and television deflection circuits. It drives the high-voltage flyback transformer in horizontal scanning stages.

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Description
Product Details

BU2508A High-Voltage Line Output Transistor – LOPT for CRT Displays

The BU2508A is a specialized high-voltage NPN transistor designed for demanding deflection applications in CRT-based displays. As the modern replacement for older TO-3 packages, the TO-247 plastic case combines robust switching performance with efficient heat dissipation. It is the proven workhorse for 21-inch and larger color television horizontal deflection stages.

Functions & Applications

High-Voltage Rated: Purpose-built for the extreme voltage switching demands of LOPT and flyback transformer applications.
Efficient Power Dissipation: TO-247 package with metal tab for secure mounting to heatsink, handling significant thermal load.
Fast Switching: Optimized for horizontal deflection frequencies typical in CRT displays.
Critical Note – No Built-in Damper Diode: The 'A' suffix indicates absence of internal protection diode; ensure your design accounts for flyback spikes.

Technical Specifications

Parameter	Value / Specification
Transistor Type	BJT (Bipolar Junction Transistor)
Polarity / Channel	NPN
Package / Case	TO-247
Collector-Emitter Voltage (Vceo)	1500V
Max Collector Current (Ic)	8A
Mounting Type	Through-Hole (THT) with Metal Tab

Frequently Asked Questions

Q: What is the difference between BU2508A and BU2508D?
A: The BU2508D includes a built-in damper diode for flyback protection; the BU2508A (no 'D' suffix) does not. If your original circuit used a BU2508D, you must add external protection or source the diode version.

Q: Do I need a heatsink with thermal paste?
A: Yes. Despite the plastic TO-247 case, the switching losses in LOPT deflection are substantial. Always mount to an aluminum heatsink using thermal compound to ensure reliable operation and longevity.

Notes

Legacy industrial/professional part designed for CRT deflection. High-voltage and high-frequency demands require careful circuit design and heatsinking. The 'A' suffix (no damper diode) is critical – verify compatibility with your original schematic.

Note: Price refers to one (1) piece. The component is shipped in bulk without individual packaging.

Transistor Type: BJT (Bipolar Junction Transistor)
Transistor Polarity / Channel: NPN
Transistor Case Style: TO-247

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