Relay question

[shot]

Hi,

I've encountered a situation I don't understand.

I'm perfboarding a relay to switch few signals simultaneously. It's a 12V relay - [ur=http://www.mouser.com/ds/2/418/RT2pb0411-205066.pdfl]TE RT424012F[/url]

Whenever I switch it for the first time it acts as it should. I measure 12V across the coil and relay closes. But when I switch the coil off and back on, next time I get around 3.7V across the coil. And of course, relay doesn't switch.

I have put the 1n4007 diode (also tried 1n4841 during the troubleshoot) and 100nF cap across the coil, the diode is I believe correctly oriented (from the ground to positive)... supply voltage is okay...

Why is this happening?

I don't undestand!

:-[

 

[PRR]

The relay is probably not the problem. What are you powering it with and how are you switching the power?

If you doubt the relay, use a fresh 9V battery and bare-wire "switching". (Yes, a "12V" relay will clack with a fresh 9V, unless it is a monster like for starting cars.)