A1930 generally refers to the 2SA1930, a high‑current PNP bipolar junction transistor (BJT) used in power amplifier and switching circuits. It’s often found in audio amplifier output stages paired with a complementary NPN transistor like 2SC5171.

📌 Key Characteristics (2SA1930)

• Transistor Type: PNP silicon BJT

• Polarity: PNP

• Package: TO‑220‑3 (through‑hole power package)

• Collector–Emitter Voltage (Vᴄᴇo): ~–180 V (maximum)

• Collector Current (Iᴄ): ~–2 A continuous

• Power Dissipation: ~20–40 W range depending on mounting/heatsink

• DC Current Gain (hFE): Moderate to high (varies with manufacturer/spec version)

• Transition Frequency (fT): Typically suitable for audio and general power stages

Note: The exact voltage and power ratings can vary slightly between manufacturer datasheets (Toshiba, ON Semiconductor, etc.), but the –180 V/–2 A class is typical for the standard 2SA1930.

🔍 Typical Applications

2SA1930 (A1930) is most commonly used in:

• Audio power amplifier output stages
  – Often paired with 2SC5171 as the complementary NPN transistor in push‑pull configurations

• Power switching circuits requiring a PNP device with decent current and voltage capacity

• Power supplies and motor controls (where a PNP transistor is needed in the high‑side path)

🔄 Complementary Pair

• 2SC5171 — NPN high‑voltage transistor commonly used with 2SA1930
  (complements the PNP behavior for push‑pull stages)

If you want, I can show you datasheet excerpts or help you find modern replacement equivalents for 2SA1930 based on your project’s voltage, current, and power needs.