Speedo Reed Switch

[Joel]

I'm trying to test the operation of a magnetic speedo reed switch by rigging it up with a lamp in the line. The lamp illumiates when you pass the sensor past a magnet, but then stays illumiated for a variable amount of time afterwards (several seconds usually). Does anyone know if this is normal or should it switch on and off much quicker than that?

 

Cheers.

[Longboarder]

That sounds like electronickery to me. Try it with just an LED so the current flows are much smaller. May give a better indication without the slow decay.

 

Nigel

[Joel]

Will do. Thanks.

[Joel]

Ok, tried with a LED and the switch is instant. So presumably that's working ok, There's power to the reed switch. Magnet clearance is good. Can't get a peep out of the speedo though!

 

Any ideas where to start???

 

The speedo does have power, in the sense that it illuminates and there's a digital odometer, but there's no life from the actual needle.

 

Cheers.

[fry61]

Just a thought -- probably wrong -- can you reverse the polarity on the speedo input;you may be trying to power it below zero.