basic question..pls clarify

[sandy_m2k2]

wat is the loss occuring in pnp transistor as switch called?

 

[elec-eng]

do u mean power loss in transistor

 

[pter_parker]

Hi,

it changes from one transistor to another, but if you are talking about dissipated power in transistor, you will find it in its datasheet.

Good luck.

 

[Meridian]

wat is the loss occuring in pnp transistor as switch called?

As mentioned before, it depends on what type of pnp transistor. There are literally thousands of them. Can you narrow it down to a specific type or series?

 

[v_c]

I think you might be referring to conduction loss. This is just Iec*Vec product when the device is "on". In power mosfets, this is characterized by the on-resistance of the device (Rds,on).

Best regards,
v_c

 

[hdrzaman]

its only because of bulk resistance of transistor due to which losses occur when used as a swtich

 

[raghu_836]

Hi

I think the power dissipation in the pnp transsitor will be p = VDD IC

where Ic = Betta * Ib

so u get dc power dissipatin.

 

[hakeen]

Hello

If you meant switching loss of pnp transistor, it is the loss during the transition of the state of transistor. Think your open collector output is high. That means transistor is off (eg collector=5V) and there is no current flow (except small leakage current). So V*I is nearly zeor. Similarly when transistor is activated, there is a current flow on the transistor but output voltage is nearly zero. Thus again V*I is very small. However during transition time (from 5 to 0 or vice versa), but voltage and current is non-neglgible. Thus switching losses dependent on frequency happens.

I guess it helps.

Regards