This post explains for the MOSFET.
The Part Number is K2837, 2SK2837.
The function of this semiconductor is 500V, 20A, N-Channel MOSFET.
Manufacturer: Toshiba Semiconductor
Preview images :
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Pinout: 1. Gate 2. Drain ( Heat Sink ) 3. Source
Description
The K2837 is Silicon N Channel MOS Type Field Effect Transistor.
Features
1. Low drain−source ON resistance : RDS (ON) = 0.21 Ω (typ.)
2. High forward transfer admittance : |Yfs| = 17 S (typ.)
3. Low leakage current : IDSS = 100 μA (max) (VDS = 500 V)
4. Enhancement mode : Vth = 2.0 to 4.0 V (VDS = 10 V, ID = 1 mA) […]
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Absolute Maximum Ratings (Ta = 25°C)
1. Drain to source voltage: VDSS = 500 V
2. Gate to source voltage: VGSS = ± 30 V
3. Drain current: ID = 20 A
4. Drain Power Dissipation: Pd = 150 W (Tc = 25°C)
5. Channel temperature: Tch = 150 °C
6. Storage temperature: Tstg = -55 to +150 °C
Applications:
1. Chopper Regulator
2. DC−DC Converter and Motor Drive