Need a mosfet...What the heck is a Mosfet?

[DaveP]

Magnifier Head Strap With Lights

This is good for the money. I've used one like it to solder 64 pin horizontal and vertical driver ICs on my 65" wide screen circuit boards. It's also great for checking solder for bridges after you get through.

I use a paper clip wrapped tightly around the soldering iron tip to create a new tiny tip. Leave about 1/3" to 1/2" protruding from the tip. This is good for tiny connections that don't need high heat.

 

[perlionsmitnick]

I am using a TI CSD16325Q5C for a touch switch with 100M resistor between gate and source and 47k res from gate to touch point. Also using a TI 5v boost board.

Does anyone know why when I touch the touch points and everything works that the voltage would start out at 5 volts then after a few seconds drop down to 4 volts? Also when I remove my finger it takes around 3 seconds for the voltage to completely drop out. Is this normal?



Thanks.

 

[MahBohMan]

I am using a TI CSD16325Q5C for a touch switch with 100M resistor between gate and source and 47k res from gate to touch point. Also using a TI 5v boost board.

Does anyone know why when I touch the touch points and everything works that the voltage would start out at 5 volts then after a few seconds drop down to 4 volts? Also when I remove my finger it takes around 3 seconds for the voltage to completely drop out. Is this normal?



Thanks.

I used a 1K ohm resistor between the touch point and the gate, with a 2-4 mega ohm resistor from gate to source and a IRL3103 with zero problems or issues, it works flawless

I've used this setup with 3.7v and 5v no prob

 

[WillyB]

I am using a TI CSD16325Q5C for a touch switch with 100M resistor between gate and source and 47k res from gate to touch point. Also using a TI 5v boost board.

Does anyone know why when I touch the touch points and everything works that the voltage would start out at 5 volts then after a few seconds drop down to 4 volts? Also when I remove my finger it takes around 3 seconds for the voltage to completely drop out. Is this normal?

Not familiar with such fancy mosfets, but I would look towards the "100M resistor between gate and source".

Seems like overkill, I'd try values from 10M - 50M.

 

[perlionsmitnick]

Not familiar with such fancy mosfets, but I would look towards the "100M resistor between gate and source".

Seems like overkill, I'd try values from 10M - 50M.

I was just going by what Scubabatdan had posted in post #19

 

[Mentat Ix]

For smallest size, I would go with the TI chip:
Power MOSFET - Power MOSFET Transistor - CSD16325Q5C - TI.com

The resistor would go here on the TI chip:

So the only wires you have left to run would be pos to the atty and pos to the switch directly from the battery.

Yes you can use the 100M, but I would use it only if I was running a touch switch, otherwise I would use the 4.7M. Remember if you run a touch switch you still need the 47k resistor between the G terminal and the touch point.

I would really recommend using SMD resistors as you can solder them directly to the TI chip and your foot print would be very samll ulike the through hole resistors.



Thanks for the vote of confidence Bubo

Hope this helps
Dan

I got some of these dang things, and I can't make anything stick to them. I'm trying to stub off them with some wire to stick it on a pcb, and it just ain't working...

 

[perlionsmitnick]

Use a dab of flux on everything and be sure to clean everything with alcohol when finished.

I used pieces of resistor wire to connect to it then moved a smt resistor out away from the chip and soldered to tiny wires.

 

[WillyB]

Or just use one of the many TO-220 case mosfets.