How to connect a relay. - Electronic Circuits Projects Diagrams Free

Lac · 15th April 2004, 07:27 PM

When you shall connect a relay, it's a + and a - pin. Shall I connect + to 5V and - to GND? or some other way?

Thanks!

Optikon · 15th April 2004, 10:27 PM

Quote:

Originally Posted by Lac

When you shall connect a relay, it's a + and a - pin. Shall I connect + to 5V and - to GND? or some other way?

Thanks!

If the relay coil is rated for 5V, then yes, + goes to 5V and - goes to ground. Your 5V supply also needs to be able to deliver the amount of coil current the relay needs. That is roughly, Isupply = 5V / coil resistance.

Coil resistance may be located on the relay datasheet.

Reminder: Don't forget the flyback diode!

Sebi · 16th April 2004, 08:51 AM

If the relay coil marked with + and - , it contain a flyback diode.

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15th April 2004, 07:27 PM	(permalink)
Lac	How to connect a relay. When you shall connect a relay, it's a + and a - pin. Shall I connect + to 5V and - to GND? or some other way? Thanks!

16th April 2004, 08:51 AM	(permalink)
Sebi	If the relay coil marked with + and - , it contain a flyback diode.