What type of relay do I want?

[legoman666]

Hi,

I need a small relay that will close when it detects 5 (or 12v) DC. I'm looking through on mouser and there's just so many choices that I have no idea what exactly to get.

Any help? We learn about all of this crap at school, but that doesn't actually teach you anything practical...

 

[mpilchfamily]

Just make sure the voltage you want on it is within the limits of the coil. So in your case you want a relay with a coil voltage of about 12VDC. Also be sure of how much current it will be receiving so you don't burn out the relay.
http://www.mouser.com/Search/R...&Keyword=relay&FS=True

 

[dbcooper1]

If you're just switching a single line on, you'll just need a SPST with a coil voltage of whatever you're applying to the control circuit. If you are switching more than one circuit you'll want a DPST. If you're switching BETWEEN circuits, you'll want a SPDT or DPDT. Number of poles=circuit(s) controlled; number of throws=circuits switched between.

 

[legoman666]

Originally posted by: mpilchfamily
Just make sure the voltage you want on it is within the limits of the coil. So in your case you want a relay with a coil voltage of about 12VDC. Also be sure of how much current it will be receiving so you don't burn out the relay.
http://www.mouser.com/Search/R...&Keyword=relay&FS=True

There will probably be no current flowing through it. Should I stick a resistor in series to get some current flowing?

 

[dbcooper1]

Huh? If you apply voltage to a coil, there WILL be current flowing. You might want to add a current limiting resistor if there isn't already one in the circuit or relay. You might also want to add a clamping diode across the coil to protect the switching device if it's a transistor. Put it across the coil of the relay, in parallel and make sure you get the polarity right.

 

[legoman666]

Originally posted by: dbcooper1
Huh? If you apply voltage to a coil, there WILL be current flowing. You might want to add a current limiting resistor if there isn't already one in the circuit or relay. You might also want to add a clamping diode across the coil to protect the switching device if it's a transistor. Put it across the coil of the relay, in parallel and make sure you get the polarity right.

Ah, I misunderstood.

Thanks for the help, I'll be getting this one: http://www.mouser.com/Search/P...virtualkey817-JY-12H-K

 

[SilentRunning]

Originally posted by: legoman666

Originally posted by: dbcooper1
Huh? If you apply voltage to a coil, there WILL be current flowing. You might want to add a current limiting resistor if there isn't already one in the circuit or relay. You might also want to add a clamping diode across the coil to protect the switching device if it's a transistor. Put it across the coil of the relay, in parallel and make sure you get the polarity right.

Ah, I misunderstood.

Thanks for the help, I'll be getting this one: http://www.mouser.com/Search/P...virtualkey817-JY-12H-K

Data Sheet:

JY- 12 H ( )-K

Nominal Votage: 12 VDC
Coil Resistance: 720 O
Must Operate Voltage: 8.4 VDC
Must Release Voltage: 0.6 VDC
Nominal Power: 200 mW

The contacts are rated at 5A.

EDIT Nevermind I see you said 5V or 12V