Typical efficiency

[kivig]

Hi,
I've bought a 200mW ebay red line laser for scanning.
It seems to be weaker than a couple of others I have got previously.
It shows current draw of 117mA @5V, while typically I see 280mA in specification of alike ones.
May or may not the typical efficiency allow 200mw at that current?
I've red in some threads here that 18-25% is top efficiency, but not sure if it was meant about red lasers.

 

[Cyparagon]

That depends on the type of driver used. But even if the driver was 100% efficient, the overall power input is on the low side. I suspect you are correct and that the power is under 100mW.

 

[kivig]

Thanks.
Just to be clear - the seller claims 200mW measured optical output, before line lens.
Total consumption calculates to about 585mW, so the diode plus driver must total in 34% efficiency together, for this to be physically possible. I wonder if 34% is something at least remotely close to what exists in reality.

 

[KRNAZNBOY]

No way it is putting out 200mw. Sorry

For 200mw red you typically need about 300-400ma in, and that is AFTER the driver.

You should open a claim or get your money back if possible.

 

[kivig]

Well, I opened a case and wrote an angry letter

 

[Lotus_Darkrose]

No way it is putting out 200mw. Sorry

For 200mw red you typically need about 300-400ma in, and that is AFTER the driver.

Definitely seems to be the case. My LOC that does a tad over 200mW with acrylic lens draws around 410-420mA at the tailcap off of a fresh battery.

Also, I made a pointer out of a flat red diode and used a single 7135 chip, and it draws exactly 350mA and does around 170mW with acrylic lens.

It is either a lower powered diode, a crappy driver, or a combination of both.