Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

Buy Site Supporter Role (remove some ads) | LPF Donations

Links below open in new window

FrozenGate by Avery

I need help finding a micro-switch






You are going to have a very hard time tracking down any switch with a reasonable tactile feel that can handle more than 50mA.

There are basically two classes of momentary switches, tact switches (What you have) and pushbutton switches. A tact switch is designed to have a tactile feel and is only designed to take a few mA to indicate on/off. A pushbutton switch generally feels more squishy and is larger but is intended for carrying a large amount of power. A tactile switch will also generally mount to a PCB while a pushbutton will have a nut for mounting to a panel with wires.

Personally, I prefer momentary switches and am currently using a tact switch rated for 100mA (You just have to look very hard) for my PHR build at ~120mA. The chances are that it will fail eventually but that is something I am willing to deal with in my build. A 50mA switch might be satisfactory if you are also using a duty cycle.

For higher quality work I use the tact switch to turn a power transistor on and off. I consider this the best option since you get the nice feel of a tact switch with the ability to switch well over an amp.

There are of course exceptions to the rule but finding nice switches is an absolute pain in the ass since you cant describe a "nice" feeling switch in a datasheet.
 
691175002 said:
You are going to have a very hard time tracking down any switch with a reasonable tactile feel that can handle more than 50mA.

There are basically two classes of momentary switches, tact switches (What you have) and pushbutton switches.  A tact switch is designed to have a tactile feel and is only designed to take a few mA to indicate on/off.  A pushbutton switch generally feels more squishy and is larger but is intended for carrying a large amount of power.  A tactile switch will also generally mount to a PCB while a pushbutton will have a nut for mounting to a panel with wires.

Personally, I prefer momentary switches and am currently using a tact switch rated for 100mA (You just have to look very hard) for my PHR build at ~120mA.  The chances are that it will fail eventually but that is something I am willing to deal with in my build.  A 50mA switch might be satisfactory if you are also using a duty cycle.

For higher quality work I use the tact switch to turn a power transistor on and off.  I consider this the best option since you get the nice feel of a tact switch with the ability to switch well over an amp.

There are of course exceptions to the rule but finding nice switches is an absolute pain in the ass since you cant describe a "nice" feeling switch in a datasheet.
Click to expand...
Were did you get yours???
 
Tech_Junkie said:
Were did you get yours???
Click to expand...
My 100mA rated switches are K12 series from digikey ( http://sigma.octopart.com/1254/datasheet/ITT-K12P-BK-1.5-5N.pdf ). They are probably too large for what you need and digikey doesn't stock the variations.

I believe there are a few 100mA rated small tact switches in the digikey/mouser catalogs but I don't have part numbers. Your best bet would be a transistor.
 
hold on...i need to look up a part #...

edit:
how about these?

mouser part #
688-SKHHAQ

688-SKHHBW

both are 50ma though :(
 
drew said:
both are 50ma though :(
Click to expand...
Yeah that's the problem. There are tons of high power pointers out there with momentary switches, I don't see why it so hard to find one for my application. :'(
 
john lawson said:
I put a 1990's AM/FM cassete deck  switch in my infinity 95 100 mw cni unit
Click to expand...
My cassette deck went out when CD's came in ;D

Maybe I can trash an old VCR. Still have those around for the nudie films. The DVD controller is to hard to manipulate with the left hand. ::)
 
You might try looking in computer mice. The clicky buttons are microswitches that can handle a decent current. I have one that is 3A at 125, but its tiny. The only downside is the audible click when you activate it.
 
Also you have to understand that while a switch is rated at 50ma @ 12vdc it's going to be able to handle a little more current @ 3vdc

Might as well try the switch you've got and see if it works. If it does your out nothing more and have a solution that works. If it doesn't then you'r no worse off than you are now. You know that you need to find another at that point which is where you think you are now.
 
Kenom said:
[highlight]Also you have to understand that while a switch is rated at 50ma @ 12vdc it's going to be able to handle a little more current @ 3vdc[/highlight]

Might as well try the switch you've got and see if it works.  If it does your out nothing more and have a solution that works.  If it doesn't then you'r no worse off than you are now.  You know that you need to find another at that point which is where you think you are now.
Click to expand...

That's key.. I agree 100%. If you lower the voltage to 1/4 of the maximum voltage rating then it should be able to handle 4X the current.. If 12V = 50mA, then 3V = 200mA. You shouldn't have any problem with the switch you have now..
 
ALPS# SKHHAK409A
You can't get better than an ALPS switch and these are four for a dollar.
I don't have anything to do with Allelectronics, other than shopping there. It's a good place.

http://www.allelectronics.com/make-a-store/item/PB-126/SUB-MINI-PC-MOUNT-PUSHBUTTON/-/1.html

image_product.align.center;height.250;vspace.5;width.150;modified.1207856745.PB-126.jpg
 
ElektroFreak said:
That's key.. I agree 100%. If you lower the voltage to 1/4 of the maximum voltage rating then it should be able to handle 4X the current.. If 12V = 50mA, then 3V = 200mA. You shouldn't have any problem with the switch you have now..
Click to expand...

This is incorrect.  A switch rated 50mA and 35V (The rating on most microswitches) will not withstand half an amp at 3V (You would weld the contacts instantly).  If the switches rating was 50VA then you might be right, however when dealing with switch ratings you cannot exceed either the current or voltage rating safely.

Microswitches were never intended to carry power, only provide enough current for a low/high in a digital circuit.

Finding 100mA rated switches isnt that hard. Just do a mouser search for tact switches and filter current > 100.
http://www.mouser.com/Search/Refine.aspx?N=254110+4294640078+4294643234+4294642636+4294641005

There are quite a few in very small packages.
 
691175002 said:
[quote author=ElektroFreak link=1236739970/0#10 date=1236788149]That's key.. I agree 100%. If you lower the voltage to 1/4 of the maximum voltage rating then it should be able to handle 4X the current.. If 12V = 50mA, then 3V = 200mA. You shouldn't have any problem with the switch you have now..
Click to expand...

This is incorrect.  A switch rated 50mA and 35V (The rating on most microswitches) will not withstand half an amp at 3V (You would weld the contacts instantly).  If the switches rating was 50VA then you might be right, however when dealing with switch ratings you cannot exceed either the current or voltage rating safely.

Microswitches were never intended to carry power, only provide enough current for a low/high in a digital circuit.

Finding 100mA rated switches isnt that hard.  Just do a mouser search for tact switches and filter current > 100.
http://www.mouser.com/Search/Refine.aspx?N=254110+4294640078+4294643234+4294642636+4294641005

There are quite a few in very small packages.[/quote]
Very nice. Thank you
 
691175002 said:
[quote author=ElektroFreak link=1236739970/0#10 date=1236788149]That's key.. I agree 100%. If you lower the voltage to 1/4 of the maximum voltage rating then it should be able to handle 4X the current.. If 12V = 50mA, then 3V = 200mA. You shouldn't have any problem with the switch you have now..
Click to expand...

This is incorrect.  A switch rated 50mA and 35V (The rating on most microswitches) will not withstand half an amp at 3V (You would weld the contacts instantly).  If the switches rating was 50VA then you might be right, however when dealing with switch ratings you cannot exceed either the current or voltage rating safely.

Microswitches were never intended to carry power, only provide enough current for a low/high in a digital circuit.

Finding 100mA rated switches isnt that hard.  Just do a mouser search for tact switches and filter current > 100.
http://www.mouser.com/Search/Refine.aspx?N=254110+4294640078+4294643234+4294642636+4294641005

There are quite a few in very small packages.[/quote]


That's good to know.. in most cases with electronics (power supplies, for example) if you lower the voltage, you can squeeze a bit more current through..
 
You must log in or register to reply here.





Back
Top