[SOLVED] Transistor doesn't reach CUTOFF region.

[Mo_Sh]

Hi,

I am doing a simple circuit, a PN2222A transistor is switched on by a 5v and a 11v on the collector.
The problem is that when I ground the base I don't get 11 volts on Vout instead I get 7.5 volts.
Why this is happening?!
The circuit is as follows (I am connecting the base to the ground as this is the case that has the problem)

 

[betwixt]

It should be 11V because the transistor shouldn't be conducting. Either the transistor is bad, you have it wired incorrectly or your voltmeter is drawing a lot of current!
7.5V is a likely value you might see if two of the transistor pins are crossed over, it is the kind of voltage you expect from a PN junction in it's breakdown region.

Brian.

 

[keith1200rs]

I guess you have connected it incorrectly. 7.5V would be a typical reverse Vbe breakdown. Check your connections

Keith.

 

[Venkadesh_M]

May be source direction changed ?? or change in transistor connection....

 

[Mo_Sh]

Yup it's inverted, I inverted the transistor and it works okay now, however this connection is the opposite to what is mentioned by the datasheet .... weird.
Thanks all.

 

[keith1200rs]

Be careful - some pictures of transistors show the view from the bottom, some the view from the top.

Keith