How to connect a 8-pin SPST reed relay? - Electronic Circuits Projects Diagrams Free

Wuey · 28th July 2005, 01:52 PM

I need to use a 12-v SPST pcb reed relay on a circuit. I have one of these in mind:

I've been googling all over to look at the pin specs without success. Can someone please tell me which are the coil pins and which are the switch pins. There is a small indent on one end of the relay. Thanks.

heathtech · 28th July 2005, 01:59 PM

Here is the datasheet. The indention on an IC indicates where pin number one starts. If you look at the IC with the indention pointing upward, pin one is the first pin next to the indention on the left side.

This datasheet will tell you the pin configuration.

http://media.digikey.com/PDF/Data%20...RM(A,%20E).pdf

looks like the left side is numbered 1,2,6,7 from top to bottom, with right side being 14,13,9,8 top to bottom.
pins 2 and/or 13 are one side of the coil, and pin 6 is the other side. The switch is NO, and pins 1,14 are connected to pins 7,8 when the coil side is energized. Of course, you realize that there isn't really a coil, it just helps to visualize the comparison of a solid state device to a mechanical.

Wuey · 28th July 2005, 02:31 PM

heathtech, thanks for your very prompt reply. Much appreciated!

JimB · 28th July 2005, 02:54 PM

Quote:

Originally Posted by heathtech

Of course, you realize that there isn't really a coil, it just helps to visualize the comparison of a solid state device to a mechanical.

Oh yes there is a coil!
This is a reed relay and needs a magnetic field to close the contacts.

JimB

heathtech · 28th July 2005, 03:25 PM

I stand corrected!

It looked by the package that this was a solid state device. I spoke before I thought. Thank you for the correction.

Wuey · 29th July 2005, 05:22 AM

Just to confirm that this isn't a solid state chip. When I apply a triggering voltage between pin 2 and pin 6, there is a very distinct clicking noise when the contact switch is activated.

heathtech · 29th July 2005, 02:30 PM

Yes, I was very wrong when I made that statement. I learned something. It is amazing how engineers have miniaturized this stuff to the point where a mechanical relay can be put in a teeny DIP!

audioguru · 29th July 2005, 05:04 PM

Since it has a coil, I bet it makes a high voltage spark when you (or a driver transistor) disconnects its current.
Therefore it needs a reverse-connected diode across it to arrest the high voltage so that the driver transistor doesn't get busted. :lol:

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28th July 2005, 01:52 PM	(permalink)
Wuey	How to connect a 8-pin SPST reed relay? I need to use a 12-v SPST pcb reed relay on a circuit. I have one of these in mind: I've been googling all over to look at the pin specs without success. Can someone please tell me which are the coil pins and which are the switch pins. There is a small indent on one end of the relay. Thanks.

28th July 2005, 01:59 PM	(permalink)
heathtech	Here is the datasheet. The indention on an IC indicates where pin number one starts. If you look at the IC with the indention pointing upward, pin one is the first pin next to the indention on the left side. This datasheet will tell you the pin configuration. http://media.digikey.com/PDF/Data%20...RM(A,%20E).pdf looks like the left side is numbered 1,2,6,7 from top to bottom, with right side being 14,13,9,8 top to bottom. pins 2 and/or 13 are one side of the coil, and pin 6 is the other side. The switch is NO, and pins 1,14 are connected to pins 7,8 when the coil side is energized. Of course, you realize that there isn't really a coil, it just helps to visualize the comparison of a solid state device to a mechanical. __________________ Freedom isn\'t Free.

28th July 2005, 02:31 PM	(permalink)
Wuey	heathtech, thanks for your very prompt reply. Much appreciated!

28th July 2005, 03:25 PM	(permalink)
heathtech	I stand corrected! It looked by the package that this was a solid state device. I spoke before I thought. Thank you for the correction. __________________ Freedom isn\'t Free.

29th July 2005, 05:22 AM	(permalink)
Wuey	Just to confirm that this isn't a solid state chip. When I apply a triggering voltage between pin 2 and pin 6, there is a very distinct clicking noise when the contact switch is activated.

29th July 2005, 02:30 PM	(permalink)
heathtech	Yes, I was very wrong when I made that statement. I learned something. It is amazing how engineers have miniaturized this stuff to the point where a mechanical relay can be put in a teeny DIP! __________________ Freedom isn\'t Free.

29th July 2005, 05:04 PM	(permalink)
audioguru	Since it has a coil, I bet it makes a high voltage spark when you (or a driver transistor) disconnects its current. Therefore it needs a reverse-connected diode across it to arrest the high voltage so that the driver transistor doesn't get busted. :lol: __________________ Uncle $crooge