LPM response times question

[gozert]

Hey all,

I have a question about LPM response times. I've seen many LPMs with 10 to 20 second response times, but some of them have times as low as 3 or 4 seconds. What exactly does having a lower or higher response time mean? I already figured out that it isn't how long it takes before the LPM registers the laser, but what exactly it does do I couldn't find.

Anyone willing to help me out?

Thanks!

 

[Pi R Squared]

It's how long it takes to read the full power. The LPM will show a power level on the meter instantly but it is less than the full power of the laser, the sensor has to be exposed to the laser for some number of seconds before it registers a correct reading, or it may be some seconds until it reads 90% power and a few more seconds until it's 100%. If you have a small high power laser that begins overheating in 30 seconds this can make it impossible to get an exact power measurement because diode lasers start dropping in power as they overheat. So a faster response time is good.

Alan

 

[Trevor]

This will probably help: http://laserpointerforums.com/f70/lpm-response-time-who-needs-84428.html

Trevor

 

[gozert]

Alright, I get most of it now. I've seen LPMs with 3-4 sec (90%), 10-12 sec (100%) response times. And I've seen LPMs with 14-16 sec (90%), 30-40 sec (100%). Is it worth buying the lower response time LPM over the higher response time LPM in this case? Considering only very low response times are good to accurately measure DPSS lasers.

And, are there any LPMs that you would recommend?

 

[gozert]

My Scienctech has a very short response time maybe a few seconds. It took me a couple months of searching in eBay but I eventually found a great set up for under 300$ including a never been used sensor thermopile.

I'll try searching for one on there then, thanks.

 

[gozert]

This looks like a good one. They normally don't have the sensor with them. Good price and it was given a basic test with a laser which is pretty uncommon.
Scientech 365 Power Energy Meter w MC2501 Power Head | eBay

That does seem like a good one indeed. Currently don't have money to spend on a LPM but I'll be looking for one in the future for sure. Thanks for taking your time to find one!

 

[gozert]

Just noticed they won't ship to The Netherlands, so even if I wanted it I wouldn't be able to get it. Would be nice if someone else from LPF can get their hands on it.

 

[Pman]

I own a couple units and although my inexpensive backup is surprisingly accurate there's nothing like a quick response unit. Love my custom Ophir