Questions about uln2003

[anju420]

ok...why do we connect a zener at the common pin of uln2003 and give the zener to the +12V supply? what rating should the zener have?

 

[alexan_e]

There is no need for a zener,
there is already an internal diode that is used as a back EMF protective diode for inductive loads,
you just have to connect the common pin to the positive supply.

Alex

 

[prabhukaran3]

[Sure Alex.. It will work properly.. no problem will arive....

 

[FvM]

There is no need for a zener,
there is already an internal diode that is used as a back EMF protective diode for inductive loads,
you just have to connect the common pin to the positive supply.

I remember several applications where a zener diode is appropriate. E. g. if the ULN is switching loads with multiple and sequenced power supply. Or you want to allow a higher back e.m.f. for faster release of contactors or solenoid valves.