relay set reset problem.. pls help

[deepakchikane]

Dear all..

I am having following relay

**broken link removed**

This negative polarity,5v operated relay..

Pls find the circuit of relay set reset..

it is not functioning in circuit... pls help me drive this relay thru emitter follower..

i tried all the resistor to the base but bjt is not acting as switch...

pls help me understand emitter follower..

will this circuit works

Deepak

 

[andre_luis]

Assuming that control signals By-pass and Reset are TTL logic based, the circuit probably will not work.
You must employ PNP transistors to perform direct drive to this relay.


+++

 

[goldsmith]

Dear all..

I am having following relay

**broken link removed**

This negative polarity,5v operated relay..

Pls find the circuit of relay set reset..

it is not functioning in circuit... pls help me drive this relay thru emitter follower..

i tried all the resistor to the base but bjt is not acting as switch...

pls help me understand emitter follower..

will this circuit works

Deepak

Hi Deepak
If you just wanna use the load in emitter , you must know that when the BJT will act as a perfect switch ( approximately ) , that , the biasing signal be exactly across the BE junction with preparing the maximum base current which is allowed .

If you wanna , do it with CE arrangement only , you have many ways e.g using a driver which can be based on another transistor or many other ways . but the simplest way is using a PNP instead .

Best Wishes
Goldsmith