connecting transistor to an LM324 to drive a 5v relay

[bodia]

I've one movement sensor that work with an LM324, how to connect a transistor for switching one relay any time the sensor detects a movement, thanks for your comments

 

[IanP]

For a basic configuration see picture below ..

Regards,
IanP

 

[bodia]

many thanks for your suggestion IanP, I'll try it and let you know.

 

[Mr.Cool]

make sure your transistor is rated for the application.

what is your relay's winding resistance? take your bus voltage and divide by that and this is the "hold" current. now you need derating on top of that so.

device rating * 0.7 >= (bus voltage)/(relay resistance)

also when the relay first turns on there is an 'inrush' current which is called umm.. i forget now. but generally you can expect this spike of current to be almost 7 times your hold current!! so, your transistor better be rated for that too.

Mr.Cool

 

[bodia]

Hi Mr. Cool

many thanks for your comment, the relay I'm using is one SIP SERIES DRY REED RELAY DSS41A05BR - DSS4 RELAY, 1FA, 500 OHMS, 5V. Contact Form:, 1A/1B, Contact Rating:, 10, Switching Voltage:, 200, Switching Current:

very similar to this one : 9007 Reed Relay
Spartan Series foud at : https://www.cotorelay.com/

my bus voltage comes frome a 9v battery...

I think this relay already has an internal diode accross the coil...

Regards

bod