Wiring questions for tactile switches and LDO

[Skyway]

No one seems to know the question in the madvapes forum so I hope someone here might have an idea.
madvapes sells a 5v LDO 3amp with control pin chip and they say it can be used for mosfet purposes for wiring in tactile switches.

Anyone every work with these before? I dont want to have to go through the trouble of getting some mosfets now that I have already bought 2 of these LDO's.

 

[Java_Az]

whats wrong with wiring it up like this?

Source of image is madvapes site 5volt 3amp reg product page.

 

[Skyway]

Hoogie apparently answered my post in the madvapes section after I posted this here. Your pic above apparently does work as intended for even 3.7v I just do not have to worry about the caps.

 

[WillyB]

That cap ain't even in the ballpark of being right anyway, and that 470Ω resistor should be a much higher value if you really want to cut the current the switch handles significantly.

 

[AttyPops]

That cap ain't even in the ballpark of being right anyway, and that 470Ω resistor should be a much higher value if you really want to cut the current the switch handles significantly.

lol. The resistor he sells with em (At least with the ones I received) has much higher ohms. The diagram ohm value is crap.

I didn't use caps on mine, been working for 2 months now.... besides, that diagram puts the cap on the output side. Correct me if I'm wrong, but wouldn't it be better to use a cap on the input to protect the mosfet? The output only would "protect"/buffer the atty since there is no inductance???? IDK.

 

[Skyway]

Hoogie stated that I did not have to use the cap. I did not use the resistor he sent with it either. I used a 470 ohm like the diagram above, I hope it will suffice. It is not getting warm or anything wrong as of yet. Project is done. It is probably the hardest one I have done so far due to all the crapped quarters with wiring it all together. Going to test it for a couple days then hot glue it.

I have to say, this lil mini 1AA box is probably going to be one of my favorites just for how small it is and how much vapor it produces.
The pump box in the third picture is the one I am going to be selling to friends and peeps at work.

 

[breaktru]

What size resistor and cap came with the kit? I have a couple of LDO's sitting in a draw with that very same diagram. So far I only have used switched regulators but who knows, may have some use for the linears in the future.

 

[Skyway]

Not sure on what the ohm of the resistor, I tried looking up the color codes but something did not line up. I either was confusing 1 or 2 of the colors with another, like brown for purple. I believe it is a orange brown orange gold but it could be yellow purple orange gold. It is so freakin small it is hard to tell. No caps came with the LDO.

 

[breaktru]

Colors on today's resistors are not like they were years ago. They are so hard to read even with a magnifying glass. Must be those cheap china crap.
Put a meter on it.

 

[CapeCAD]

Last time I ordered they were 470K ohm

 

[Skyway]

The 470 resistors I get from madvapes with the LED's are twice the size of the ones that came with the 2 LDO's I ordered. They were taped together, I guess to make sure you do not loose them. They were that small.

I will put them on a meter when I get home to see if i can get a reading.

 

[breaktru]

The 470 resistors I get from madvapes with the LED's are twice the size of the ones that came with the 2 LDO's I ordered. They were taped together, I guess to make sure you do not loose them. They were that small.

I will put them on a meter when I get home to see if i can get a reading.

Thanks Skyway. No rush, The LDO's are stored away for future use. Maybe I'll make a box mod for my son.

 

[Skyway]

Well as it turns out. Putting the voltmeter on 2M it chimes in at 470. The bigger one I used is chiming in at 470 when it set the meter on 2K.

 

[NuMoNiC]

I would use 10-47K resistor and 60-100uf cap on the input side.

 

[AttyPops]

Nice mods.

As a general rule (varies a lot) the smaller the resistor, the higher the resistance. Makes sense, the more material, the more conductivity, thus lower resistance. The small resistor is often an indicator that it is a higher value. However, this varies too much depending on the material to say for sure. I'll bet it's in the K range. You sure that it is 470 (no K)? You did use a mega-ohm setting on the meter..... Mine is auto-scale, so IDK if you mean 470 or 470 K.

Yellow -violet-yellow is 470 K
Yellow-violet-orange is 47 K
Yellow-violet-brown is 470

So it is the 3rd band issue.

BTW you're right... reading those colors is a real PITA on those small resistors.

 

[Skyway]

As it turns out. I decided to break out my camera and take a picture of them side by side in the sunlight with super macro mode on. Amazing how doing this will shed some light on things.
Bigger one is 470 and the smaller looks like 470K to me.

So in light of this. I should have used the smaller one for my switch?

 

[breaktru]

Yes the 1/2 watt (bigger one) is 470 ohm Yellow, Violet, Brown at 5% tolerance and the smaller 1/4 watt looks like Yellow, Violet, Yellow which would be 470K ohm at 5% tolerance. It's hard to judge the physical size from the photo. The 1/2 watt can really be 1/4 watt and the 1/4 watt can really be 1/8 watt.
The forth band is the tolerance, plus or minus the resistor value. Gold is 5%, Silver is 10% and no color is 20%.

 

[Skyway]

well, think of it this way. If I wanted too, I could actually insert that LED into an atty center hole.