Power Dissipation

• The 2N2222 is rated for a maximum of 625 milliwatts of power dissipation. Since much of this power is dissipated as heat, it is important to note that the junction temperature should not exceed 150 degrees Celsius or 302 degrees Fahrenheit.
  
  

Maximum Voltage Ratings

• The maximum voltage between the collector and base leads must not exceed 60 volts. The maximum voltage between the collector and emitter leads must not exceed 30 volts. The voltage between the base and emitter leads must not exceed 5 volts.
  
  

Saturation Voltage

• The voltage at which the transistor turns completely on is called the "saturation voltage." When the current at the collector lead reaches 500 milliamps and the current at the base lead reaches 50 milliamps, the saturation voltage between the base and collector is 1 volt. At these same current values, the saturation voltage between the base and emitter leads is 2 volts.
  
  

Other Considerations

• The PN2222 transistor is electrically identical to the 2N2222 transistor, and may be used as a direct substitute. The only major difference between the two transistors is the packaging type: a metal can is used for the 2N2222; a plastic case is used for the PN2222.