The 2N3906 transistor is commonly used as a switching device. When used as a switch, it can be operated in saturation region and cut-off region. In PNP transistor, by default it’s in ON state, but not to be said perfectly ON until the base pin is not grounded. If we provide ground to the base pin then the transistor will be in reverse biased and said to be turn ON. If supply is provided to the base pin it stops conducting current between emitter and collector and said to be in OFF state. For the protection of transistor a resistance added in series with it.