Persamaan Transistor D998 B778

Technical Write-Up: Equivalent Transistors for 2SD998 and 2SB778

1. Introduction

The 2SD998 (NPN) and 2SB778 (PNP) are a complementary pair of power transistors widely used in audio power amplifiers, particularly in the output stages of high-fidelity (Hi-Fi) stereo systems, home theater receivers, and professional PA amplifiers. Known for their high current handling and wide Safe Operating Area (SOA), this pair has become a standard in many Japanese-brand amplifiers from the 1980s–2000s (e.g., Pioneer, Kenwood, Technics, and Sansui).

2. Physical Packaging & Pin Configuration

Both transistors use the MT-200 (Sanyo’s large, insulated power package) or sometimes TO-3P/TO-247 variants, though the classic Sanyo MT-200 is most common.

Langkah 4: Periksa Rangkaian Pendukung (Driver)

Transistor driver (biasanya ukuran TO-220 seperti D669/B649) harus diganti jika D998/B778 short. Driver yang rusak akan membunuh transistor final baru meskipun sudah menggunakan persamaan yang tepat. Persamaan Transistor D998 B778

hFE Matching: For audio quality, buy matched pairs or measure hFE. Original parts had hFE range 40–140. Modern equivalents (e.g., 2SC5200) are typically 55–160. Close matching between NPN and PNP reduces distortion.

(full part numbers ) are a complementary pair of silicon power transistors primarily used in high-fidelity audio power amplifiers. They are designed for "push-pull" amplifier output stages, where the NPN 2SD998 handles the positive signal half-cycle and the PNP 2SB778 handles the negative half-cycle. Core Specifications These transistors are typically packaged in Siapkan AVO meter mode DC milivolt

  • Siapkan AVO meter mode DC milivolt.
  • Ukur tegangan pada resistor emitor (0.22 Ohm / 5W).
  • Putar trimpot VR bias hingga tegangan = 15 mV – 25 mV untuk kelas AB standar.
  • Jika terlalu panas, turunkan ke 10 mV.

Jika Anda ingin, saya bisa:

for a single pair, though buying in "matched lots" of 5 or 10 pairs is often more cost-effective for multi-channel amplifier repairs. or a recommendation for a specific heatsink to use with these transistors? Jika Anda ingin, saya bisa: for a single

Common failures:

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