Help with switches!!!

[Nuck]

So I've never used a mosfet. Just to be sure.... I would wire from power source -> mosfet -> switch-> atty. Is that right? AND, does the mosfet have any effect on the voltage?

I currently run 6.2 volts using two 14500's in parallel with a TI ptn04050 booster.

An n-channel mosfet (like the one listed) has a gate, drain and source.

The B- goes to the source pin.

The B+ goes to switch.

The other side of the switch goes to gate.

The drain goes to the ground on the ptn4050 board.

Another line goes from B+ to Vin on the ptn4050 board.


Btw..with a 510 atty you are pushing that ptn4050 way too hard at 6.2v and exceeding both the max power of 12w and the current limit of 2.4 amps.

 

[dmohn28]

Thanks for the info nuck.

And I'm not using a 510, I only use the be112 atty now.

 

[Ralph Hilton]

So I've never used a mosfet. Just to be sure.... I would wire from power source -> mosfet -> switch-> atty. Is that right? AND, does the mosfet have any effect on the voltage?

I use IRML2502 - the measured voltage drop is 0.04 .
Its also good to put a high value resistor - 470k is ok - from the gate to the -ve supply so that the gate isn't left floating.

 

[FizzleFisch]

I use IRML2502 - the measured voltage drop is 0.04 .
Its also good to put a high value resistor - 470k is ok - from the gate to the -ve supply so that the gate isn't left floating.

Hey Ralph!

Excellent floating gate reminder! Owing to complacency...I've overlooked that one a time or two in the past. It can make for an aggravated tail-chase on troubleshooting sometimes!

The IRML2502 datasheet I found shows it in a Micro3 SMD package. Do you make your own pcb for them or just solder-connect directly to the legs (with a microscope & hot-needle soldering iron )?

fisch

 

[Ralph Hilton]

I just direct solder.

 

[FizzleFisch]

I just direct solder.

I see! ....and on a piece of perf-board no less!

Very impressive sir!! -- Thank you for the photo img!

fisch

 

[Jason_in_nc]

Yeah, thanks for posting that Ralph.

Probably more involved work than I'm comfortable of doing at this point though...

 

[OH Tommy]

re: Help With Switches . . .

I haven't received them yet, but:

THIS IS FOR ONE PACK OF BRAND NEW HIGH QUALITY -- 16 PIECES MINI PUSH-BUTTON MOMENTARY SPST ON/OFF SWITCHES. Normally Off, Off-(On), push it " on" release it " off". CUT SIZE : 10mm 125V--6A, 250V - 3A ... $7.75 SHIPPED

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