Rq 2N2222 NPN Bipolar Transistor TO-92

2N2222 is an NPN transistor hence the collector and emitter will be left open (Reverse biased) when the base pin is held at the ground and will be closed (Forward biased) when a signal is provided to the base pin. 2N2222A has a gain value of 110 to 800, this value determines the amplification capacity of the transistor. The maximum amount of current that could flow through the Collector pin is 800mA, hence we cannot connect loads that consume more than 800mA using this transistor. To bias a transistor we have to supply current to the base pin, this current (IB) should be limited to 5mA.

When this transistor is fully biased, it can allow a maximum of 800mA to flow across the collector and emitter. This stage is called Saturation Region and the typical voltage allowed across the Collector-Emitter (V­CE) or Base-Emitter (VBE) could be 200 and 900 mV respectively. When the base current is removed the transistor becomes fully off, this stage is called the Cut-off Region, and the Base Emitter voltage could be around 660 mV.

Applications

·       Can be used to switch high-current (up to 800mA) loads

·       It can also be used in various switching applications.

·       Speed control of Motors

·       Inverter and other rectifier circuits

·       Can be used in Darlington Pair.