How to Wire Case positive Diode

[KRNAZNBOY]

Ok, this has been bugging me forever. I see two possible scenarios.

I am a laser builder but i am still not familiar with basic electronics so that is sad. Sorry

Case positive: You make the case +, but then how do you wire the driver with just the negative from the battery?

Case negative: The positive output from the driver will short with the negative case where the + goes to the diode.

SO HOW DO YOU DO IT?

This also brings something else up.

I have heard that some build require a driver with a Continuous ground. What is that VS. Non-continuous ground?

Is there continuous +?

Thanks guys
-Matt

 

[Zeebit]

Case positive: You make the case +, but then how do you wire the driver with just the negative from the battery?

You don't make the case positive because its already the positive terminal of the diode. You will need a continuous positive driver like the AMC7135. You need to connect both the positive input of the driver and the case pin to the positive pole of the battery.

Case negative: The positive output from the driver will short with the negative case where the + goes to the diode.

Opposite of case positive. The case serves as a negative pole of the diode.
I don't seem to understand why you think the positive driver output will short with the diode. You need a continuous negative driver for this.
I am not aware of which drivers are continuous negative but you can check it with a multimeter. Set it to ohms mode and probe the input and output of the driver (+ in to +out; -in to -out). The terminal that shows 0 ohms is the continuous rail.


Some drivers are neither continuous positive nor negative like the buck driver from DX. I'm not totally sure about this but as far as I understand this is not continuous on neither rails.

 

[KRNAZNBOY]

Ok, cool. I know moh's linear drivers were continuous ground. What about drivers like the x-drive/boost series and the flexdrives?

Thanks
-Matt

 

[Zeebit]

Ok, cool. I know moh's linear drivers were continuous ground. What about drivers like the x-drive/boost series and the flexdrives?

Thanks
-Matt

I have no idea. I have not built anything with those drivers...yet. I think the x-drive is not continuous on niether rails. Better ask lazeerer about the drives.

When you build a laser that requires a case connection, make sure that the host has an electrical connection to the heatsink. Some hosts like the C6 are not electrically connected to the heatsink. Also, anodized heatsinks do not conduct electricity.

 

[Jufran88]

I'm pretty sure you can use any driver for a case positive laser diode. The trick is isolating the case pin. The case pin is usually connected to the body of the diode where it touches the heat sink. This makes the usually negative feed to the body of the host positive.

Another trick would be to feed the battery backwards so the body of the host is also positive. An example of this would be green laser pointers.

Here's a wiring diagram from drlava:

Hopefully that helps!

 

[KRNAZNBOY]

So there is no way to do it like a 445. You have to isolate something. Would using an anodized heatsink work as an isolator?

This is confusing, augg.

I don't understand how people do it, build red builds. How can you isolate a battery from the case? WHAT?

And how is it possible to isolate the diode from the case, when it is a CASE + diode...

Fill me in please
-Matt

 

[Jufran88]

Using an anodized heat sink would work well for case positive builds.

Case positive diodes makes a positive feed throughout the host instead the the usual negative/ground. Since the battery makes a negative feed throughout the host it will interfere and kill the diode. So isolating the diode from the rest of the host will work or reversing the battery. Hope that helps!

 

[expertmagician]

Hi ... I am new....
Want to buy a 50mW laser diode and simply connect it to a 1.5 volt battery.

The diode has a typical operating voltage of 1.5 volts and max of 1.7 volts.
It typically operates at 95 mA with a max of 120mA

I do know that a battery may not last long...that is OK.

But, I was thinking that f I simply connected a 1.5 Volt battery to the diode, I should not blow out the diode since the battery is only 1.5 volts ?

Thoughts ? Can I avoid using any other parts other than a battery and the diode ?

Thx !

 

[10fenny]

what about a driver on this necro post?