PCB Power (On/Off) Switch and Fuse Recommendation

Dave,

First off, welcome to the community. There are several active people here willing to help and be helped.

Switches are extremely plentiful in their size, shape and function.  I could not find any info on RDT1034 part, so I am not sure that I can help you with this part.  If you have more information, like a specification sheet, or even a snapshot of the switch in the schematic and layout, it might be able to help in understanding the form/fit/function that is needed.

The fuse is also problematic, in that fuses come in many varieties and have several parameters (trip/blow current, slow/fast blow, physical dimensions).  Again, a better understanding of the design would be helpful to select a proper component (same as above, more information would help).

Good luck!

Gene

Thanks Gene.  I appreciate the feedback and help!  My freelancer was from Russia (I think, his profile said US...) and used older libraries.  I am trying to use components that are available in an Eagle Library and that I have an exact part number to place on the board and order.  I'm getting wrapped around the axle on that point.

The RDT1034 in the board looks like this (no other property values are available):

This is how he laid out the power-in for the schematic.   Honestly, since I'm using a barrel jack, I really don't need the switch and my breadboard currently has no fuse.  So, from a prototyping perspective, I could probably just eliminate them for now.  But, it's got to be better to have them even if it's a prototype board.

I suspect that there are a thousand suitable replacements for the RDT1034.   For example, this one:

I think this is what he specified for the fuse holder.

Hi Dave,

You possibly don't need the fuse, because the diode inline (1N4148) doesn't support a lot of current anyway, and will probably blow open before the fuse does. What value was the fuse rated at?

Dave,

It gets a little weird when you work with some people in remote locations and they are using older versions of the software.

Depending on how you deploy your design, yeah the switch might not be necessary.  If you are going to use a switch now, the one you linked to could be used if you are wiring it in remotely, as the footprint on the layout does not match with this switch.  If you are intending to mount the switch on the PCB, you will need another switch.

On the topic of fuses, it is still difficult to determine the value of the fuse that would be needed, without understanding the expected current draw.  The line of fuses for use with this holder range from 40mA all the way up to 10A.  You need to pick one that would cover your normal range of operation, which some headroom for inrush or other surges (within normal operation). I am a little ashamed to say this, but on low-voltage boards, like this, I do not usually install a fuse.  If there were some regulatory requirements that needed to be met, I would, but for the most part that has not been the case.  The protective device in most cases is the attached power supply.  Most are capable of shutting down on an over-current situation.

Good luck,

Gene

Dave,

It gets a little weird when you work with some people in remote locations and they are using older versions of the software.

Depending on how you deploy your design, yeah the switch might not be necessary.  If you are going to use a switch now, the one you linked to could be used if you are wiring it in remotely, as the footprint on the layout does not match with this switch.  If you are intending to mount the switch on the PCB, you will need another switch.

On the topic of fuses, it is still difficult to determine the value of the fuse that would be needed, without understanding the expected current draw.  The line of fuses for use with this holder range from 40mA all the way up to 10A.  You need to pick one that would cover your normal range of operation, which some headroom for inrush or other surges (within normal operation). I am a little ashamed to say this, but on low-voltage boards, like this, I do not usually install a fuse.  If there were some regulatory requirements that needed to be met, I would, but for the most part that has not been the case.  The protective device in most cases is the attached power supply.  Most are capable of shutting down on an over-current situation.

Good luck,

Gene

Thanks Gene!  I've got some work to do.  I'm going to start over and use only parts that I can find through design link.  There are only a handful of parts on this design too.  I've lost way too much time trying to second guess what he's done.

On Thu, 18 Jan 2018 21:40:20 GMT, Gene Breniman

If protection is needed, ditch the fuse and use a polyfuse instead.

This is a specially designed thermistor that "opens" at a designated

amperage but resets when it cools off.

John

wrote:

On the topic of fuses, it is still difficult to determine the value of the fuse that would be needed, without understanding the expected current draw.  The line of fuses for use with this holder range from 40mA all the way up to 10A.  You need to pick one that would cover your normal range of operation, which some headroom for inrush or other surges (within normal operation). I am a little ashamed to say this, but on low-voltage boards, like this, I do not usually install a fuse.  If there were some regulatory requirements that needed to be met, I would, but for the most part that has not been the case.  The protective device in most cases is the attached power supply.  Most are capable of shutting down on an over-current situation.

 

Good luck,

Gene

John DeArmond

http://www.neon-john.com

http://www.tnduction.com

Tellico Plains, Occupied TN

See website for email address