electronics help please

[oneyearwonder]

i have a pcb with some double pole momentary action switches mounted on it, and am looking to replace them, possibly with illuminated switches. but of this type do the switches come with three terminals on the back- positive, switched +ve and negative for the illumination??? this is assuming that the switch is single pole- the ones i have are DP but bridged across. im an electrician but not been an electronic-ician since school, so help would be much appreciated

 

[ricicle]

If they are illuminated switches then yes they will normally require a Neg as well.The lamp is across switched Pos and Neg.

 

[davelx]

They will have 4 terminals - the switch contacts and the illumination will be totally independant.

 

[ricicle]

They will have 4 terminals - the switch contacts and the illumination will be totally independant.

Not always - it depends on the make/type

 

[bernardgreen]

This is not going to be an easy task unless you are very lucky and the type of switch fitted is already one of a series that also inlcudes illuminated switches and they use a common footprint ( layout of holes in the PCB )

 

[davelx]

They will have 4 terminals - the switch contacts and the illumination will be totally independant.

Not always - it depends on the make/type

Maybe but I've seen 100's of different types and never seen one with a common switch/lamp contact designed for electronic. ie signal/logic level applications. I think you'd have to search for one.

Then again, I could jsut have been unlucky

 

[Space cat]

Is this a single sided PCB? If it's double sided and through-hole plated you'll be doing well to get the old switches out. Next, as bernardgreen says, you'll need replacement switches with the same footprint and even then you'll have to modify the track layout.

If you can't find anything that slots straight in it gets even worse because now you'll have to drill holes. Check that the board isn't multi-layer before you do this.

 

[Spark123]

How much space have you got to mount the switch? Does it matter if the switch is separate from the illumination? EAO do various combinations of switches but are pretty expensive

 

[Spark123]

They will have 4 terminals - the switch contacts and the illumination will be totally independant.

Not always - it depends on the make/type

Maybe but I've seen 100's of different types and never seen one with a common switch/lamp contact designed for electronic. ie signal/logic level applications. I think you'd have to search for one.

Then again, I could jsut have been unlucky

I have seen them in 12v rocker switches for cars, can't remember seeing them in 5v ttl though. Don't think they were momentary either.

 

[tim west]

As bernard stated before unless the tracks on the pcb are already configured to allow an illuminated switch then it could get messy adding the function, it may entail drilling more holes ,adding more bulky wiring and components, power requirements may have to change calling for installing a new regulator.
Is the illuminated switch feature an absolute necessity?