Problem with positive case pin and negative host

[poseidon05]

I'm trying to build a 505nm pen pointer and am using a sharp gh05030c2lm diode, which has the positive pin as the case pin. The problem is it's in a brass heatsink which touches the interior of the host, which is negative. So instead of the positive current going into the diode, it just escapes through the heatsink to the host and goes back to the battery. I confirmed this by touching a wire to the negative end of the battery and the outside of the heatsink, and the laser turns off. Also, there is no room to insulate the heatsink from the host because it's a perfect fit (see pic).

The only solution I can think of is to file off the outside of the heatsink to make room for insulation (maybe electrical tape) but I'm wondering if anyone has any other ideas or if I'm missing something.

 

[Shmackitup]

You'll either need to reconfigure the host as case positive or insulate the diode/module from the host. Heat-shrink tubing or electrical tape may work or perhaps an insulating layer of glue, epoxy or silicone caulking applied ever so carefully.

 

[poseidon05]

You'll either need to reconfigure the host as case positive or insulate the diode/module from the host. Heat-shrink tubing or electrical tape may work or perhaps an insulating layer of glue, epoxy or silicone caulking applied ever so carefully.

If I make it case positive then the positive current from the battery would go straight to the diode without going through the driver. Wouldn't that kill the diode?

 

[Shmackitup]

If I make it case positive then the positive current from the battery would go straight to the diode without going through the driver. Wouldn't that kill the 4diode?

You would need to reverse the driver if possible. It probably wouldn't do anything at all if you just flip the batteries around.

 

[poseidon05]

You would need to reverse the driver if possible. It probably wouldn't do anything at all if you just flip the batteries around.

What do you mean by reverse the driver?

 

[Shmackitup]

What do you mean by reverse the driver?

The polarity........

 

[poseidon05]

The polarity........

How

 

[Shmackitup]

How

probably a soldering iron

 

[wolfram]

Can someone draw a crude diagram for him. Nube needs pic........................He wants to save his money.

 

[Shmackitup]

Can someone draw a crude diagram for him. Nube needs pic........................He wants to save his money.

I think it would just be easier if he simply isolated the diode.

 

[wolfram]

a bit of heat sink compound would do it.

 

[ZRaffleticket]

I've had success with scotch tape to isolate. These diodes don't kick out a lot of heat. Just check for continuity before turning it on

 

[Lifetime17]

Hi,
Kempton tape its thin and I used it many time to isolate the problem.
Rich

 

[loreadarkshade]

I don't recommend isolating the diode from the host as it will warm up quite quickly and may damage it
You'll need an isolated boost driver to drive this diode, and have to install the battery backwards with positive touching the entire host body

I have some case neutral 505nm diodes if you want to skip the hassle of trying to find an isolated boost driver, shoot me a pm

Or you can try this driver:

https://vi.aliexpress.com/item/1005004602483365.html?gatewayAdapt=glo2vnm

 

[Lifetime17]

I don't recommend isolating the diode from the host as it will warm up quite quickly and may damage it
You'll need an isolated boost driver to drive this diode, and have to install the battery backwards with positive touching the entire host body

I have some case neutral 505nm diodes if you want to skip the hassle of trying to find an isolated boost driver, shoot me a pm

Or you can try this driver:

https://vi.aliexpress.com/item/1005004602483365.html?gatewayAdapt=glo2vnm

I made many 505 builds and not one ever spoiled with Kempton tape . The wattage it very low on the 505's and dontheat up very much. This isn't my first rodeo ..
Rich