Transistor is not switching.

[deepakdkt]

Hi,
i was working on a circuit in which i got BC177 PNP transistor. getting 3.8 voltage @base of transistor , but still its not switching. Transistor is in working condition.
how much voltage exactly required by the transistor to switch ?
the transistor circuit is followed by the voltage divider circuit.

Thank you,
Deepak

 

[milan.rajik]

Show your circuit. 0.7V is enough to forward bias base emitter junction. Maybe your voltage divider has high resistances and Ib might be very less. Make Ib = 1 or 2 mA.

 

[deepakdkt]

Sir, I have attached the image of the circuit.. Please go through this.

Thank you.

 

[asking]

PNP means it requires Negative Supply on the Base Terminal to operate. Giving Positive Supply it will be in off position.

 

[FvM]

What's connected to the open collector? How do you determine "switching"?

 

[deepakdkt]

@FvM
Sir there is a pull down resistor connected to collector which i dint mentioned in the given circuit.

 

[FvM]

The circuit is able to source several mA to the pull-down resistor.
In so far it's "working", I think.

 

[deepakdkt]

the problem is solved.
Thank you all ..
i changed the transistor and checked the circuit , now its working ..
might be the diode within the transistor was weak , so it was not switching.
now i am getting 5v @collector

 

[asking]

That's great you got it working....