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Science Forum Index » Electronics - Basics Forum » activating reed switch...
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| lerameur... |
 Posted: Fri Jul 25, 2008 2:24 pm |
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Hello,
I made myself a small electromagnet to activate a reed switch using a
6v supply. The problem is that I am pulling 3 amps, I do not want the
electromagnet to be bigger by making more turns, I believe there are
such electromagnet on the market that can activate a reed switch with
current in the milliamps. anybody know such device, I looked at
digikey and mouse but I did not find anything under electro magnet.
thanks
ken |
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| Tim Wescott... |
| Posted: Fri Jul 25, 2008 7:32 pm |
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lerameur wrote:
Quote: Hello,
I made myself a small electromagnet to activate a reed switch using a
6v supply. The problem is that I am pulling 3 amps, I do not want the
electromagnet to be bigger by making more turns, I believe there are
such electromagnet on the market that can activate a reed switch with
current in the milliamps. anybody know such device, I looked at
digikey and mouse but I did not find anything under electro magnet.
thanks
ken
Try using finer wire.
Look under "solenoid".
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html |
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| Paul E. Schoen... |
| Posted: Fri Jul 25, 2008 8:40 pm |
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"Tim Wescott" <tim at (no spam) seemywebsite.com> wrote in message
news:BemdnV9SCYkb7RfVnZ2dnUVZ_vjinZ2d at (no spam) web-ster.com...
Quote: lerameur wrote:
Hello,
I made myself a small electromagnet to activate a reed switch using a
6v supply. The problem is that I am pulling 3 amps, I do not want the
electromagnet to be bigger by making more turns, I believe there are
such electromagnet on the market that can activate a reed switch with
current in the milliamps. anybody know such device, I looked at
digikey and mouse but I did not find anything under electro magnet.
thanks
ken
Try using finer wire.
Look under "solenoid".
You could also try a capacitor and resistor in parallel to drive a quick
surge of 3 amps to activate the reed relay, and the resistor to provide
just enough current to keep it activated. I have done this to operate AC
relay coils using DC.
Paul |
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| Bob Eld... |
| Posted: Fri Jul 25, 2008 9:21 pm |
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Guest
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"lerameur" <lerameur at (no spam) yahoo.com> wrote in message
news:e8cba1a2-1aa8-4e4f-ba59-b9624d250236 at (no spam) b1g2000hsg.googlegroups.com...
Quote: Hello,
I made myself a small electromagnet to activate a reed switch using a
6v supply. The problem is that I am pulling 3 amps, I do not want the
electromagnet to be bigger by making more turns, I believe there are
such electromagnet on the market that can activate a reed switch with
current in the milliamps. anybody know such device, I looked at
digikey and mouse but I did not find anything under electro magnet.
thanks
ken
Yes they have reed relays that draw 10mA at 6 volts. Three amps means you
don't have nearly enough turns and, of course, the wire you are using is a
1000 times too fat.
If you are serious about it you'll have to wind them with AWG 44 or thinner
wire. Good luck finding that. Good luck winding that with 10,000 turns. Not
a job for the timid.
Look for reed relays under relays. Jameco has them. |
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| Michael Black... |
| Posted: Fri Jul 25, 2008 9:26 pm |
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On Fri, 25 Jul 2008, Bob Eld wrote:
Quote:
"lerameur" <lerameur at (no spam) yahoo.com> wrote in message
news:e8cba1a2-1aa8-4e4f-ba59-b9624d250236 at (no spam) b1g2000hsg.googlegroups.com...
Hello,
I made myself a small electromagnet to activate a reed switch using a
6v supply. The problem is that I am pulling 3 amps, I do not want the
electromagnet to be bigger by making more turns, I believe there are
such electromagnet on the market that can activate a reed switch with
current in the milliamps. anybody know such device, I looked at
digikey and mouse but I did not find anything under electro magnet.
thanks
ken
Yes they have reed relays that draw 10mA at 6 volts. Three amps means you
don't have nearly enough turns and, of course, the wire you are using is a
1000 times too fat.
If you are serious about it you'll have to wind them with AWG 44 or thinner
wire. Good luck finding that. Good luck winding that with 10,000 turns. Not
a job for the timid.
Look for reed relays under relays. Jameco has them.
That brings up what the original poster is wanting to use this for.
I was going to say "well can't you buy coils to activate them" and then
I realized standalone reed switches are mostly activated by a permanent
magnet.
So there either has to be a better way, or the poster needs a different
method.
Figure out a mechanical system to move the permanent magnet in close
to activate the switch.
Take apart an existing relay for the coil, and use that.
Or figure out why a normal relay can't be used; there may be
reasons, such as the reed switch has a more direct contact for
RF use, but there really should be a good reason to do it this
way rather than a "normal" relay.
At this point, I'm even willing to believe that the original
poster is unaware of regular relays.
Michael |
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