This post explains for the transistor.
Part Number: 2N2222A
Function: Silicon Planar Epitaxial NPN Transistor
This is 40V, 800mA, NPN Transistor.
The 2N2219A and 2N2222A are silicon Planar Epitaxial NPN transistors in Jedec TO-39 (for 2N2219A) and in Jedec TO-18 (for 2N2222A) metal case. They are designed for high speed switching application at collector current up to 500mA, and feature useful current gain over a wide range of collector current, low leakage currents and low saturation voltage.
ABSOLUTE MAXIMUM RATINGS
1. Collector-Base Voltage (IE= 0) : VCBO = 75 V
2. Collector-Emitter Voltage (IB= 0) : VCEO = 40 V
3. Emitter-Base Voltage (IC= 0) : VEBO = 6 V
4. Collector Current : IC = 0.6 A
5. Collector Peak Current (tp< 5 ms) : ICM = 0.8 A
Other data sheets are available within the file: 2N2219A, 2N2222