I need a momentary on switch that can handle around 40 volts and 3-4A current. I see plenty of 36V 2A DC switches. Do you all think they will hold up? I am looking at something like this
How about just switching an FET?
I need a momentary switch to use with a trigger system. I don’t know how I could use a FET as a switch in this situation
FET just carries the current so any momentary switch you can fit would work. Just need both B+ and B- to the FET.
Yeah, you just went over my head Scott. How would that be wired?
If it’s a momentary on switch, it wouldn’t be handling the current for very long would it? If that is the case, wouldn’t the switch you linked be sufficient?
It’s going on a trigger system. It will have the current as long as I hold the trigger down.
Depends upon the type of load. If the load is pure resistance, I wouldn’t worry about it, the switch should work fine.
However if it is reactive load such as a Motor, don’t try it. When you open the circuit, the magnetic field in the motor windings collapses, and the you would be surprised at just how high a voltage you can get. You can quite literally arc weld the contacts together that way. Because of that problem, most DC switches are rated very conservatively.
Wouldn't an automotive switch work? There are tons of styles available that would surely take the current...
The FET doesn’t need a pcb and has three pins; gate, drain, and source. This one is rated at 40V ,120A.
Run B+ to the led(s) (fat wire) and one side of the switch (thin wire).
Run led- to the drain tab of the FET (fat wire).
Run wire from source pin to B-(fat wire).
Run wire from other side of switch to gate(thin wire).
When switch is pressed power is applied to gate, current flows through FET and LEDs go whoopee! Switch can be momentary or toggle(locking), a reverse clicky is both and since very little current flows through the switch almost any can be used.
I can’t explain it but in my experience funny things happen at about 5 amps and around 40-50VDC. A lot of arcing goes on and switches get eaten up. There’s something about that combination, as though it’s a sweet spot for arcing.
Maybe I’m just crazy.
EDIT:
I forgot to mention that you could use an FET from a discarded Li-Ion drill pack. Most 18V packs have 2 automotive type power FET’s
Cool!
There are lots of them, some rated 40V drain to source but only +/- 20V gate to source. I have no idea if that’s an issue so I looked up one rated at 40V on both. You should be able to find one at mouser that has a screw hole tab but I don’t think it’s necessary to have that just one big enough to solder easily and glue it in place after wiring.