P2N2222A is an obsolete NPN transistor that I found an alternate for, here are the relevant specifications:
| Specification | Value |
|---|---|
| Transistor Type | NPN |
| Transition Frequency | 300MHz |
| Voltage Collector-Emitter Breakdown (MAX) | 40V |
| Mounting Type | Through Hole |
| Package/Case | TO-226-3, TO-92-3 Long Body |
| Current Collector Max (Ic) | 600mA |
There are many similar parts with similar part numbers compared to P2N2222A that have pretty close specifications: Single Bipolar Transistors | Bipolar (BJT) | Transistors | Electronic Components Distributor DigiKey where you could substitute with the following part.
Here is what I found: 2N4401-ND; 2N4401BU
Please review the datasheets to ensure the alternative will work for your application.