This is where a PNP transistor differs from a NPN transistor, a Logic state (blue colour) is used to toggle between Ground and Signal Voltage (Emitter-Base Voltage VBE) as shown below.The maximum amount of current that could flow through the Collector pin is 200mA, hence we cannot connect loads that consume more than 200mA using this transistor.To bias a transistor we have to supply current to base pin, this current (IB) should be limited to 5mA.
This stage is called Saturation Region and the typical voltage allowed across the Collector-Emitter (VCE) or Base-Emitter (VBE) could be 40 and 5 V respectively. When base current is removed the transistor becomes fully off, this stage is called as the Cut-off Region and the Base Emitter voltage could be around 5V. It very much similar to the bc557 transistor except for that it has high collector to emitter voltage and hence high voltage loads can be toggled. This transistor has only a gain value of 300, hence not suitable for amplifier circuits. When used as a switch, it can be operated in saturation region and cut-off region. In PNP transistor, by default its in ON state, but not to be said perfectly ON until the base pin is not grounded. ![]() If supply is provided to the base pin it stops conducting current between emitter and collector and said to be in OFF state. ![]() ![]() 2N3906 Transistor Datasheet Series With ItSo, from that you can find the value of resistance to be added in series with it. In the below circuit the base emitter voltage (VBE) is 0V (Grounded) hence the PNP transistor conducts and the motor rotates. Note that for PNP transistors the loads should be connected in the collector side as shown below. Also note that the load current should be less than 200mA (here 140ma).
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