This post explains for the transistor.
The Part Number is 2D717, D717.
The function of this semiconductor is 70V, 10A, NPN Transistor.
The package is TO-3P(I)D Type
Manufacturer: Wing Shing Electronic
Preview images :
D717 is 70V, 10A, NPN Transistor. Silicon NPN high frequency, high power transistors in a plastic envelope, primarily for use in audio and general purpose.
A NPN transistor is a type of bipolar junction transistor (BJT) that consists of two n-type semiconductor materials separated by a single p-type material.
The NPN transistor is used to amplify or switch electronic signals and is widely used in many electronic circuits. It works by controlling the current flow between the collector and emitter terminals through the base terminal.
When a small current is applied to the base, it controls a much larger current between the collector and emitter, making the NPN transistor an effective amplifier or switch.
Absolute maximum ratings ( Ta=25°C )
1. Collector to Base Voltage: Vcbo = 70 V
2. Collector to Emitter Voltage: Vceo = 70 V
3. Collector Current: Ic = 10 A
4. Collector Dissipation : Ptot = 80 W