This post explains for the semiconductor A1943.
The Part Number is 2SA1943.
The Package is TO-3P Type
The function of this semiconductor is PNP Transistor.
Manufacturers : Toshiba
TOSHIBA Transistor Silicon PNP Triple Diffused Type 2SA1943
Applications : Power Amplifier
• High collector voltage: VCEO = −230 V (min)
• Complementary to 2SC5200
• Recommended for 100-W high-fidelity audio frequency amplifier output stage.
Absolute Maximum Ratings (Ta = 25°C)
Characteristics Symbol Rating Unit Collector-base voltage VCBO −230 V Collector-emitter voltage VCEO −230 V Emitter-base voltage VEBO −5 V Collector current IC −15 A Base current IB −1.5 A Collector power dissipation (Tc = 25°C) Junction temperature Storage temperature range PC 150 W Tj 150 °C Tstg −55 to 150 °C JEDEC JEITA TOSHIBA ― ― 2-21F1A Note: Using continuously under heavy loads (e.g. the application of high Weight: 9.75 g (typ.) temperature/current/voltage and the significant change in temperature, etc.) may cause this product to decrease in the reliability significantly even if the operating conditions (i.e. operating temperatu […]