Using a relay

It looks like the 5 volt DC coil is connected between pins 3 and 5.

When unpowered, there should be a (normally) closed contact between pins 4 and 2.

When 5 volts is connected to the coil, there should be a contact closure between pins 4 and 1.

Check the resistance between pins 3 and 5, to see if it is a reasonable resistance for a 5 volt coil. I would expect a resistance between 25 and 100 ohms.

What you have is a single pole double throw (SPDT) relay. The coil is rated for 5 VDC, and the contacts are rated for up to 10A at 250VAC.

NO and NC are, as you surmised, normally open and normally closed. Pins 3 and

Specifically:

- no current across pins 3 & 5: pin 4 is connected to pin 2, and not to pin 1

- 5VDC across pins 3 & 5: pin 4 is connected to pin 1, and not to pin 2

Whether this is something you can use, depends on what your application for it might be.

Doug Miller skrev:

It works, thanks :)

seems wierd to have the com so close to the 5vdc, since it can be dangerous voltage ?

/Jan

I agree. I would not use this relay to switch line voltage, unless the 5 volt supply was completely and safely isolated from any chance of being touched, and was referenced to the voltage applied to the common.

John Popelish skrev:

Some time in the future I plan to switch line, but probaly with another relay, its a jungle :)

I just need a Normally Open relay rated for a few amp 230V, and triggered by 5vdc so I can do it from a logic circuit.

This one is rated for 24VDC too, so I will find some uses for it :)

Is that a Single Pole Single Throw - Normally Open then ?

/Jan

That's correct. Of course, a double-throw relay can be used in place of either a single-throw NO or a single-throw NC -- you just leave the other terminal open.

You cannot generally switch a relay from a logic circuit, logic circuit will not provide enough mA, you will need a transistor between the output and the relay

Pete D skrev:

Ok, the pics I use can handle 20mA current draw on the out pins. Still waiting for a new fuse to be able to measure amp, oops :)

/Jan

You have a point, I was thinking logic gates not MPU, just thought it worth mentioning, as the original poster didn't know how to wire a relay, i suspect not using a MPU. Of course I could be wrong, I usually am ;-)

Pete D skrev:

I am the OP :) I started playing with electronics a few months ago, so even after a lot of reading, its still pretty basic.

I am using the picaxe, not a "real" pic but a lot faster to code on (mostly because I dont know c, cpp or assembly).

but yes its worth mentioning, I already killed one of their medium range chips, not sure how, but resistors and making sure not to draw much more than a relay, transistor or led from the pins could be a start :)

/Jan

Oh mine is pretty basic, after a mere 30 years, sokeep plugging away at it

If you want to program 'real' PIC's but want to stick to Basic, have a look at

The Finder website isn't working so trying to get data is hopeless. Nevertheless, The Relays-R-Us website in the UK does have some info on the 36 series